423 ошибка http

Обычные посетители сайта обращают внимание в первую очередь на качественный контент, а поисковые краулеры – на ответы сервера.

Сегодня научимся проверять код как одной страницы, так и всех сразу, а также разберем все коды ответа и узнаем, что именно они означают.

Немного теории

Определить доступность веб-страницы поможет анализ кода состояния HTTP. Технически он представляет из себя стандартный запрос. Он отправляется, когда мы переходим по определенной ссылке на сайте или просто вводим ее в поисковой строке браузера. При обработке запроса сервер самостоятельно формирует и отдает трехзначный цифровой код.

Благодаря коду ответа понять реакцию сайта на запрос может не только поисковый краулер, но и обычный пользователь. Здесь нет ничего сложного даже для начинающих вебмастеров.

Сперва определимся с терминами.

• Клиент – компьютер, смартфон или другое мобильное устройство, которое имеет подключение к интернету.
• Сервер – определенный компьютер, который хранит все данные сайта (включая страницы и системные файлы). Именно на сервере «живет» сайт.

Выделяют пять классов ответов. Идентифицировать класс можно по первой цифре.

• 5** – техническая ошибка на стороне сервера. Точная причина указывается сразу после кода. Иногда пятисотая говорит о внутренних сбоях, реже – о превышении статической нагрузки на сервер.
• 4** – сбой на стороне юзера.
• 3** – обнаружен редирект на другой адрес (не ошибка).
• 2** – запрос обработан успешно (не ошибка).
• 1** – служебный класс кодов, который чаще всего относится к информационным сообщениям (не ошибка).

Логика кодов, таким образом, весьма проста:

Что значат коды состояния HTTP

Причины / решения / пояснения ошибок, я буду давать только для самых часто встречающихся кодов. Для всех остальных – только краткое описание.

Двухсотые – успешные запросы

200 – успешный запрос данных. Код не является ошибкой.

201 – завершена успешная транзакция. Код говорит о том, что сформирован новый ресурс (или документ).

202 – запрос принят, но еще не завершен. Необходимо дождаться окончания обработки.

203 – данные получены не из первоисточника (возвращаемые данные идут не от исходного сервера, а от какого-то другого) и могут быть устаревшими.

204 – запрос был обработан правильно, но отсутствует содержимое. Есть заголовок ответа, но содержимое для него отсутствует. Обновлять и актуализировать содержимое не нужно.

205 – клиенту необходимо осуществить сброс содержимого. Саму страницу обновлять не требуется.

206 – ошибка частичного содержимого. Если клиент хочет выполнить загрузку данных в несколько потоков, а сервер выполняет только часть GET-запроса, будет возникать 206-ая ошибка.

GET-запрос предназначен для получения данных, в то время как POST-запрос нужен для отправки данных.

Код также может быть отправлен с сервера, когда клиент запросил диапазон (например, условно: «Дайте мне первые 2 МБ видеоданных»). Происходит возврат только частичного контента, соответствующего Range-заголовку (данный заголовок дает понять серверу, какую именно часть страницы от него требуют, и какую ему нужно вернуть).

Если страница отдает этот код, следует обратить внимание на выполнение кэширования и на исходящий запрос.

207 – выполнено несколько операций. Найти их можно в XML, в строке MultiStatus.

226 – обработан IM-заголовок. Содержимое будет возвращено для получения информации об ответе вместе с ранее обозначенными параметрами.

Трехсотые – запросы на редирект

300 – не удалось идентифицировать точный URL. Такой ответ возникает, когда существует множественный выбор, и краулер не знает, к какой именно странице относится ресурс.

301 – документ был навсегда перемещен на новый URL. Так должны отвечать все веб-страницы, которые удалены или являются зеркалами, дублями. Со временем все указанные страницы будут склеены с целевой веб-страницей (присоединены к ней) автоматически. Если возникает такая ошибка, нужно настроить 301-ое перенаправление с устаревшего URL на актуальный (если речь идет о веб-странице, которая уже ранжировалась, но ее URL изменился). В таком случае все позитивные метрики, включая вес URL, будут сохранены.

302 – документ был временно перемещен на новый URL. Это абсолютно корректный ответ сервера, который актуален для веб-страниц с распродажами или сезонными акциями, распространяющимися на какой-либо товар. Код указывает, что данный URI будет учитываться клиентом в последующих запросах. Другими словами, страница была найдена, но перенесена. Такие документы из индекса не удаляются. Если адрес был изменен навсегда, вместо 302-го, лучше использовать 303-ий или 307-ой ответ.

303 – нужно направить пользователя на иной URL. 303-ый код можно получить исключительно GET-запросом. В идеале, этот код нужно отдавать, когда требуется редиректнуть посетителя на близкорелевантую, но не идентичную странице.

304 – документ не модифицировался. Этот код не является стандартным редиректом. Он помогает краулерам определять страницы, которые не изменились с последнего визита.

Если на вашем сайте немного страниц (до 1 000), использовать код 304 нет смысла. Если вас напрягает этот редирект, то в заголовке нужно поправить параметр Last-Modified (последняя дата изменения) – он не должен быть старше, чем заголовок If-Modified-Since (если изменялся спустя заданное количество времени).

305 – доступ к этому документу возможен исключительно через прокси.

307 – документ был временно перемещен на иной URL. Идеальный вариант, если требуется временно редиректнуть посетителя, но оставить техническую возможность отправки POST-запросов.

Четырехсотые – сбои на стороне клиента

400 – ошибка синтаксиса. Сервер не может идентифицировать запрос, так как была допущена опечатка в синтаксисе. Проверьте корректность отправляемого запроса.

401 – отсутствует аутентификация. Код отдается, когда для доступа требуется пароль или регистрация.

403 – отсутствует доступ к документу. Возникает, когда пользователь хочет открыть системные файлы (robots, htaccess). Либо вы сделали опечатку при вводе URL и пытаетесь воспользоваться веб-страницей, которая не предназначена для обычного пользователя, либо вам нужно: пройти авторизацию для доступа к системным файлам.

404 – отсутствует соответствующий ресурс по введенному URL. Разберитесь, по каким причинам была удалена / перемещена страница. Возможно, вы допустили ошибку и удалили ее случайно. Если так – просто восстановите ее.

Задумайтесь над созданием красивой, кастомизированной 404-ой. Например, такой:

405 – некорректный метод (указывается в запросной строке клиента) для выбранного документа. Метод запроса определяет точное действие, которое должно быть выполнено для указанного ресурса.

406 – некорректный / неподдерживаемый краулером формат запроса. Код отдается, когда сервер не способен возвратить ответ, релевантный листу допустимых значений. Самый распространенный случай – поисковый робот не поддерживает кодировку документа или его язык. Убедитесь, что в теле сообщения содержится лист доступных ресурсов. Подробное описание ошибка на сайте веб-разработчиков Mozilla.

407 – отсутствует регистрация прокси или авторизация файервола.

408 – таймаут запроса. Соединение разорвано, так как полный запрос не был передан. Другими словами, запрос занял слишком много времени, а сервер не готов был ждать. На каждом сайте существует свое время таймаута. Проверьте наличие интернета и просто обновите страницу. Подробное объяснение этой ошибки на сайте веб-разработчиков Mozilla.

409 – несовместимость двух запросов. Запрос невозможно выполнить при текущем состоянии сервера. Самый распространенный случай – операции c PUT-запросом. Например, когда нужно скачать файл, возраст которого превышает возраст уже существующего, расположенного на сервере.

410 – ресурс более не существует по указанному URL. Если страница удаляется целенаправленно, лучше делать так, чтобы она отдавала именно 410-ый. Краулер обойдет такую страницу, получит этот код и больше никогда на нее не вернется, так как поймет, что она удалена навсегда. Если речь о веб-странице, которая была удалена временно, гораздо эффективнее использовать 404-ый ответ. Если страница удалена намерено и навсегда, но в SERP имела хорошие места и приносила трафик, лучше сделать редирект на максимально релевантную существующую страницу.

411 – сервер сам отклоняет отправляемый запрос, так как не находит значение Content-Length. Этот ответ характерен как для обычных POST-запросов, так и для PUT-запросов (подразумевают замену существующих представлений документа на данные, которые содержатся в самом запросе).

412 –не были до конца выполнены условные поля HTTP-заголовка, например, If-Match. 412-ый код появляется в случаях, когда доступ к целевому документу отклоняется. Нужно проверить соблюдение и корректность HTTP-заголовков выполняемого запроса.

413 – у каждого сервера есть свой собственный максимальный размер запроса, определяемый не самим HTTP-протоколом (у него ограничения по длине запроса просто напросто отсутствуют), а ограничениями со стороны браузеров. Браузеры поддерживают запросы от 2 до 8 килобайт. Вышеуказанный код отдается, когда сервер не понимает запрос из-за слишком большого размера.

414 – возникает, когда отправляется чрезвычайно длинный URL. Запросы, содержащие излишне длинные URL, не могут правильно интерпретироваться сервером. Самые частые случаи появления этого ответа – попытка передать удлиненные параметры (излишне большое количество данных через GET- запрос).

415 – некорректный медиаформат. Текущий тип данных не может быть интерпретирован сервером.

416 – некорректное значение Range (диапазон). Ответ возникает в случаях, когда в самом HTTP-заголовке прописывается некорректный байтовый диапазон. 416-ый отдается в случаях, когда сервер не может взаимодействовать с запрашиваемыми диапазонами. Причина – отсутствие диапазона в необходимом документе или опечатка в синтаксисе.Сервер просто не имеет возможности работать с запрашиваемыми диапазонами. Проверьте синтаксис значения Range – он должен обязательно соблюдаться. Скорее всего, документ просто не имеет запрашиваемых диапазонов. Обновите страницу.

417 – указанное значение Expect не может быть удовлетворено (речь о заголовке запроса). Прокси некорректно идентифицировал содержимое поля «Expect: 100-Continue». Устранить эту ошибку самостоятельно не удастся. Если вы используете прокси Squid, обратитесь в поддержку. Вам нужно активировать ignore_expect_100. Другой вариант ­ разрешите BS_PingHost обращаться к интернет-сети без участия прокси.

422 – существует определенная логическая ошибка. Какая именно, данный код не указывает. Копайте в сторону ошибок в семантике документа.

423 – используемый ресурс был заблокирован для выбранного HTTP—метода. Перезагрузите роутер и компьютер. Используйте только статистический IP.

424 – зависимый ресурс был блокирован по соображением безопасности. Данный код отдается, если в запросе присутствуют признаки несанкционированного доступа к файлам CMS.

426 – некорректные значения полей Upgrade и Conection. Этот ответ возникает, когда серверу требуется обновление до SSL-протокола, но клиент не имеет его поддержки.

429 – слишком много запросов. Ошибка отдается, когда один пользователь проявляет чрезмерно большую активность за короткий временной интервал. Проверьте плагины используемой CMS. В идеале, отключите их все и включайте по очереди, пока не доберетесь до источника проблемы.

451 – доступ к серверу заблокирован по решению судебных органов. Можно плодить бесконечные дубли или вообще создать новый домен, но рано или поздно страницу с идентичным содержимым все равно заблокируют. Временное решение – разместить проблемное содержимое на другом домене. Провайдеры могут подстраховаться и блокировать не только отдельные страницы, но и сайты целиком. Не нарушать закон – единственное, что можно посоветовать в этом случае.

Пятисотые – серверные сбои

500 – серверу не удается полностью обработать запрос. Такой код отдается, когда существует непредвиденное условие, мешающее выполнению запроса. Чаще всего внутренняя ошибка сервера может появляться при серверных сбоях. Проверяйте, корректно ли указаны директивы в системных файлах (особенно htaccess), нет ли ошибки прав доступа к файлам. Обратите внимание на ошибки внутри скриптов и их медленную работу.

Проверяйте конфликты плагинов и дополнений. Нередко 500-ая возникает, когда в настройках административной панели хостинга указана одна версия PHP, а на самом сайте используется другая. Последнее также создает высокую статическую нагрузку на хостинг. Если вам было бы узнать о пятисотой подробнее, пишите в комментариях, и я напишу развернутый материал на эту тему.

501 – не выполнено. Этот код отдается, когда сам сервер не может идентифицировать метод запроса. Сами вы эту ошибку не исправите. Устранить ее может только сервер.

502 – шлюзовый сбой. Возникает при получении некорректного ответа от сервера, находящегося по иерархии выше. Актуально исключительно для прокси и шлюзовых конфигураций.

503 – данный ответ возникает в случаях, когда существуют технические неполадки, не позволяющие интерпретировать введенный запрос. Скорее всего, ваш сервер просто на обслуживании или сильно перегружен. Уменьшите число перманентных запросов к базам данных. Убедитесь, что на сервере нет профилактических или других работ, ограничивающих его пропускную способность. Не используйте VPN.

504 – отсутствует ответ. Этот код отдается в одной ситуации – если сервер не может получит ответ за необходимый период времени. Отклика нет и возникает таймаут. Как и 501-ый ответ, 504-ый исправить самостоятельно не получится. Здесь дело в прокси, часто – в веб-сервере. Первым делом просто обновите веб-страницу. Если не помогло, нужно почистить DNS-кэш. Для этого используем сочетание горячих клавиш Windows+R и вводим команду cmd (Control+пробел). В открывшемся окне указываем команду ipconfig / flushdns и подтверждаем ее нажатием Enter.

Также полезно посмотреть, как страница ведет себя различных мобильных устройствах и в разных браузерах. Проверьте дебаг. Если сайт на WP, то проверить дебан проще всего. Достаточно добавить этот код в wp-config.php:

Теперь все сбои будут фиксировать в файле debug.log (находится в папке wp-сontents). Если вы используете другую CMS, найдите к ней мануал и посмотрите, как активировать в ней журнал ошибок.

Также 504-ая отдает, когда на сайте существуют проблемы, связанные с задействованием CDN или кастомизированных серверов DNS. Отключите CDN на своем сайте.

Иногда 504-ый код пропадает, если просто подождать несколько часов. Часто 504-ая появляется на сайтах, которые используют CloudFlare.

505 – отсутствует поддержка текущей версии HTTP-протокола.

507 – не хватает места на жестком диске для выполнения запроса.

510 – не найдено расширение, желающее задействовать клиент.

Массово проверяем ответ веб-страницы

Самый простой способ проверить ответ веб-страницы – воспользоваться готовыми сервисами. Наиболее популярны:

• mainspy;
• 2ip;
• cy-pr;
• wwhois;
• 4seo.

Возьмем для примера mainspy. Тут проверить код ответа проще всего:

Таким образом, для проверки кода просто открываем страницу и вводим необходимые URL. Кликаем «Проверить». Будет выведен отчет. Напротив каждого проверяемого URL будет отображаться код ответа сервера:

Кроме перечисленных сервисов есть также замечательный плагин для Google Chrome – HTTP Header Spy. Он позволяет проверять код ответа сервера как одной, так и нескольких страниц сразу:

Послесловие

Коды ответа HTTP – это универсальный язык, который понимают не только краулеры Google / «Яндекса», но и люди. 5 классов кодов позволят с первого взгляда определить, где именно существует ошибка при выполнении HTTP запроса и куда копать для ее устранения.

Если ваш код ответа не указан в этом мануале, значит речь идет о кастомизированном сервере. Чтобы правильно истолковать ответ такого сервера и перевести его на человеческий язык, придется обратится к его разработчику.

The 423 Locked status-code does not appear in the base
HTTP specification, but is part of WebDAV specification, which is an
extension to HTTP.

A major goal of WebDAV was to provide a ‘filesystem over the web’. One of its
core features is for users to ‘lock’ specific files and directories to prevent
others from editing them.

A user can lock a resource by issuing a http LOCK method and later on
unlock the resource by using the UNLOCK HTTP method.

Both ‘shared locks’ and ‘exclusive locks’ are supported.

Example

Locking a resource

LOCK /article/5 HTTP/1.1
Content-Type: application/xml

<?xml version="1.0"?>
<d:lockinfo xmlns:d='DAV:'>
 <d:lockscope><d:exclusive/></d:lockscope>
 <d:locktype><d:write/></d:locktype>
 <d:owner>Evert</d:owner>
</d:lockinfo>

A successful response to this includes a Lock-Token header.

HTTP/1.1 200 OK
Content-Type: application/xml
Lock-Token: <urn:uuid:e71d4fae-5dec-22d6-fea5-00a0c91e6be4>

<?xml version="1.0"?>
...

If a user tries to make a change to a locked resource, they will get an error:

PUT /article/5 HTTP/1.1
Content-Type: text/plain

New content

HTTP/1.1 423 Locked
Content-Type: application/xml

<?xml version="1.0" encoding="utf-8" ?>
<d:error xmlns:d="DAV:">
  <d:lock-token-submitted>
  <d:href>/article/5</d:href>
  </d:lock-token-submitted>
</d:error>

Unless, they also include the lock-token in the If header:

PUT /article/5 HTTP/1.1
Content-Type: text/plain
If: <urn:uuid:e71d4fae-5dec-22d6-fea5-00a0c91e6be4>

New content

Usage on the web

I haven’t seen a lot of usage of LOCK, UNLOCK and the 423 code outside
of WebDAV. However, I don’t see strong reasons against their usage.

A big part that the lock functionality
of WebDAV hopes to solve, is avoiding problems with multiple users making
updates on (groups of-) resources at the same time.

If you also have this issue, bear in mind that there is a more popular feature
in HTTP to deal with this: Etags and the If-Match / If-None-Match headers.

These headers tend to work a bit better, especially if they are required
because they give a strong indicator to an end-user: you are about to overwrite
someone’s changes. If ETags solve your concurrency or ‘lost update’
use-case, it’s likely better.

However, one thing LOCK does is that it allows a user to reserve a resource
in advance for editing. It basically can give an indication to other users:
“someone is currently working on this document”.

Is that problem solvable without resorting to WebDAV http methods? Probably!
Your REST resources could for example simply expose a lockedBy JSON property.
When set, it could prevent only that user to make changes.

References

• RFC4918, Section 11.3 — 423 Locked
• RFC4918, Section 9.10 — LOCK method
• RFC4918, Section 9.11 — UNLOCK method

See also:

• 412 Precondition Failed.
• WebDAV features that might be useful for HTTP services.

From Wikipedia, the free encyclopedia

This is a list of Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client’s request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the HTTP. The first digit of the status code specifies one of five standard classes of responses. The optional message phrases shown are typical, but any human-readable alternative may be provided, or none at all.

Unless otherwise stated, the status code is part of the HTTP standard (RFC 9110).

The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes.^[1]

All HTTP response status codes are separated into five classes or categories. The first digit of the status code defines the class of response, while the last two digits do not have any classifying or categorization role. There are five classes defined by the standard:

• 1xx informational response – the request was received, continuing process
• 2xx successful – the request was successfully received, understood, and accepted
• 3xx redirection – further action needs to be taken in order to complete the request
• 4xx client error – the request contains bad syntax or cannot be fulfilled
• 5xx server error – the server failed to fulfil an apparently valid request

1xx informational response

An informational response indicates that the request was received and understood. It is issued on a provisional basis while request processing continues. It alerts the client to wait for a final response. The message consists only of the status line and optional header fields, and is terminated by an empty line. As the HTTP/1.0 standard did not define any 1xx status codes, servers must not^{[note 1]} send a 1xx response to an HTTP/1.0 compliant client except under experimental conditions.

100 Continue

The server has received the request headers and the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). Sending a large request body to a server after a request has been rejected for inappropriate headers would be inefficient. To have a server check the request’s headers, a client must send Expect: 100-continue as a header in its initial request and receive a 100 Continue status code in response before sending the body. If the client receives an error code such as 403 (Forbidden) or 405 (Method Not Allowed) then it should not send the request’s body. The response 417 Expectation Failed indicates that the request should be repeated without the Expect header as it indicates that the server does not support expectations (this is the case, for example, of HTTP/1.0 servers).^[2]

101 Switching Protocols

The requester has asked the server to switch protocols and the server has agreed to do so.

102 Processing (WebDAV; RFC 2518)

A WebDAV request may contain many sub-requests involving file operations, requiring a long time to complete the request. This code indicates that the server has received and is processing the request, but no response is available yet.^[3] This prevents the client from timing out and assuming the request was lost.

103 Early Hints (RFC 8297)

Used to return some response headers before final HTTP message.^[4]

2xx success

This class of status codes indicates the action requested by the client was received, understood, and accepted.^[1]

200 OK

Standard response for successful HTTP requests. The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request, the response will contain an entity describing or containing the result of the action.

201 Created

The request has been fulfilled, resulting in the creation of a new resource.^[5]

202 Accepted

The request has been accepted for processing, but the processing has not been completed. The request might or might not be eventually acted upon, and may be disallowed when processing occurs.

203 Non-Authoritative Information (since HTTP/1.1)

The server is a transforming proxy (e.g. a Web accelerator) that received a 200 OK from its origin, but is returning a modified version of the origin’s response.^[6][7]

204 No Content

The server successfully processed the request, and is not returning any content.

205 Reset Content

The server successfully processed the request, asks that the requester reset its document view, and is not returning any content.

206 Partial Content

The server is delivering only part of the resource (byte serving) due to a range header sent by the client. The range header is used by HTTP clients to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.

207 Multi-Status (WebDAV; RFC 4918)

The message body that follows is by default an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.^[8]

208 Already Reported (WebDAV; RFC 5842)

The members of a DAV binding have already been enumerated in a preceding part of the (multistatus) response, and are not being included again.

226 IM Used (RFC 3229)

The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.^[9]

3xx redirection

This class of status code indicates the client must take additional action to complete the request. Many of these status codes are used in URL redirection.^[1]

A user agent may carry out the additional action with no user interaction only if the method used in the second request is GET or HEAD. A user agent may automatically redirect a request. A user agent should detect and intervene to prevent cyclical redirects.^[10]

300 Multiple Choices

Indicates multiple options for the resource from which the client may choose (via agent-driven content negotiation). For example, this code could be used to present multiple video format options, to list files with different filename extensions, or to suggest word-sense disambiguation.

301 Moved Permanently

This and all future requests should be directed to the given URI.

302 Found (Previously «Moved temporarily»)

Tells the client to look at (browse to) another URL. The HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect with the same method (the original describing phrase was «Moved Temporarily»),^[11] but popular browsers implemented 302 redirects by changing the method to GET. Therefore, HTTP/1.1 added status codes 303 and 307 to distinguish between the two behaviours.^[10]

303 See Other (since HTTP/1.1)

The response to the request can be found under another URI using the GET method. When received in response to a POST (or PUT/DELETE), the client should presume that the server has received the data and should issue a new GET request to the given URI.

304 Not Modified

Indicates that the resource has not been modified since the version specified by the request headers If-Modified-Since or If-None-Match. In such case, there is no need to retransmit the resource since the client still has a previously-downloaded copy.

305 Use Proxy (since HTTP/1.1)

The requested resource is available only through a proxy, the address for which is provided in the response. For security reasons, many HTTP clients (such as Mozilla Firefox and Internet Explorer) do not obey this status code.

306 Switch Proxy

No longer used. Originally meant «Subsequent requests should use the specified proxy.»

307 Temporary Redirect (since HTTP/1.1)

In this case, the request should be repeated with another URI; however, future requests should still use the original URI. In contrast to how 302 was historically implemented, the request method is not allowed to be changed when reissuing the original request. For example, a POST request should be repeated using another POST request.

308 Permanent Redirect

This and all future requests should be directed to the given URI. 308 parallel the behaviour of 301, but does not allow the HTTP method to change. So, for example, submitting a form to a permanently redirected resource may continue smoothly.

4xx client errors

This class of status code is intended for situations in which the error seems to have been caused by the client. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents should display any included entity to the user.

400 Bad Request

The server cannot or will not process the request due to an apparent client error (e.g., malformed request syntax, size too large, invalid request message framing, or deceptive request routing).

401 Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource. See Basic access authentication and Digest access authentication. 401 semantically means «unauthorised», the user does not have valid authentication credentials for the target resource.

Some sites incorrectly issue HTTP 401 when an IP address is banned from the website (usually the website domain) and that specific address is refused permission to access a website.^{[citation needed]}

402 Payment Required

Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, as proposed, for example, by GNU Taler,^[13] but that has not yet happened, and this code is not widely used. Google Developers API uses this status if a particular developer has exceeded the daily limit on requests.^[14] Sipgate uses this code if an account does not have sufficient funds to start a call.^[15] Shopify uses this code when the store has not paid their fees and is temporarily disabled.^[16] Stripe uses this code for failed payments where parameters were correct, for example blocked fraudulent payments.^[17]

403 Forbidden

The request contained valid data and was understood by the server, but the server is refusing action. This may be due to the user not having the necessary permissions for a resource or needing an account of some sort, or attempting a prohibited action (e.g. creating a duplicate record where only one is allowed). This code is also typically used if the request provided authentication by answering the WWW-Authenticate header field challenge, but the server did not accept that authentication. The request should not be repeated.

404 Not Found

The requested resource could not be found but may be available in the future. Subsequent requests by the client are permissible.

405 Method Not Allowed

A request method is not supported for the requested resource; for example, a GET request on a form that requires data to be presented via POST, or a PUT request on a read-only resource.

406 Not Acceptable

The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request. See Content negotiation.

407 Proxy Authentication Required

The client must first authenticate itself with the proxy.

408 Request Timeout

The server timed out waiting for the request. According to HTTP specifications: «The client did not produce a request within the time that the server was prepared to wait. The client MAY repeat the request without modifications at any later time.»

409 Conflict

Indicates that the request could not be processed because of conflict in the current state of the resource, such as an edit conflict between multiple simultaneous updates.

410 Gone

Indicates that the resource requested was previously in use but is no longer available and will not be available again. This should be used when a resource has been intentionally removed and the resource should be purged. Upon receiving a 410 status code, the client should not request the resource in the future. Clients such as search engines should remove the resource from their indices. Most use cases do not require clients and search engines to purge the resource, and a «404 Not Found» may be used instead.

411 Length Required

The request did not specify the length of its content, which is required by the requested resource.

412 Precondition Failed

The server does not meet one of the preconditions that the requester put on the request header fields.

413 Payload Too Large

The request is larger than the server is willing or able to process. Previously called «Request Entity Too Large» in RFC 2616.^[18]

414 URI Too Long

The URI provided was too long for the server to process. Often the result of too much data being encoded as a query-string of a GET request, in which case it should be converted to a POST request. Called «Request-URI Too Long» previously in RFC 2616.^[19]

415 Unsupported Media Type

The request entity has a media type which the server or resource does not support. For example, the client uploads an image as image/svg+xml, but the server requires that images use a different format.

416 Range Not Satisfiable

The client has asked for a portion of the file (byte serving), but the server cannot supply that portion. For example, if the client asked for a part of the file that lies beyond the end of the file. Called «Requested Range Not Satisfiable» previously RFC 2616.^[20]

417 Expectation Failed

The server cannot meet the requirements of the Expect request-header field.^[21]

418 I’m a teapot (RFC 2324, RFC 7168)

This code was defined in 1998 as one of the traditional IETF April Fools’ jokes, in RFC 2324, Hyper Text Coffee Pot Control Protocol, and is not expected to be implemented by actual HTTP servers. The RFC specifies this code should be returned by teapots requested to brew coffee.^[22] This HTTP status is used as an Easter egg in some websites, such as Google.com’s «I’m a teapot» easter egg.^[23][24][25] Sometimes, this status code is also used as a response to a blocked request, instead of the more appropriate 403 Forbidden.^[26][27]

421 Misdirected Request

The request was directed at a server that is not able to produce a response (for example because of connection reuse).

422 Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors.^[8]

423 Locked (WebDAV; RFC 4918)

The resource that is being accessed is locked.^[8]

424 Failed Dependency (WebDAV; RFC 4918)

The request failed because it depended on another request and that request failed (e.g., a PROPPATCH).^[8]

425 Too Early (RFC 8470)

Indicates that the server is unwilling to risk processing a request that might be replayed.

426 Upgrade Required

The client should switch to a different protocol such as TLS/1.3, given in the Upgrade header field.

428 Precondition Required (RFC 6585)

The origin server requires the request to be conditional. Intended to prevent the ‘lost update’ problem, where a client GETs a resource’s state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.^[28]

429 Too Many Requests (RFC 6585)

The user has sent too many requests in a given amount of time. Intended for use with rate-limiting schemes.^[28]

431 Request Header Fields Too Large (RFC 6585)

The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.^[28]

451 Unavailable For Legal Reasons (RFC 7725)

A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.^[29] The code 451 was chosen as a reference to the novel Fahrenheit 451 (see the Acknowledgements in the RFC).

5xx server errors

The server failed to fulfil a request.

Response status codes beginning with the digit «5» indicate cases in which the server is aware that it has encountered an error or is otherwise incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and indicate whether it is a temporary or permanent condition. Likewise, user agents should display any included entity to the user. These response codes are applicable to any request method.

500 Internal Server Error

A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.

501 Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request. Usually this implies future availability (e.g., a new feature of a web-service API).

502 Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

503 Service Unavailable

The server cannot handle the request (because it is overloaded or down for maintenance). Generally, this is a temporary state.^[30]

504 Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

505 HTTP Version Not Supported

The server does not support the HTTP version used in the request.

506 Variant Also Negotiates (RFC 2295)

Transparent content negotiation for the request results in a circular reference.^[31]

507 Insufficient Storage (WebDAV; RFC 4918)

The server is unable to store the representation needed to complete the request.^[8]

508 Loop Detected (WebDAV; RFC 5842)

The server detected an infinite loop while processing the request (sent instead of 208 Already Reported).

510 Not Extended (RFC 2774)

Further extensions to the request are required for the server to fulfill it.^[32]

511 Network Authentication Required (RFC 6585)

The client needs to authenticate to gain network access. Intended for use by intercepting proxies used to control access to the network (e.g., «captive portals» used to require agreement to Terms of Service before granting full Internet access via a Wi-Fi hotspot).^[28]

Unofficial codes

The following codes are not specified by any standard.

419 Page Expired (Laravel Framework)

Used by the Laravel Framework when a CSRF Token is missing or expired.

420 Method Failure (Spring Framework)

A deprecated response used by the Spring Framework when a method has failed.^[33]

420 Enhance Your Calm (Twitter)

Returned by version 1 of the Twitter Search and Trends API when the client is being rate limited; versions 1.1 and later use the 429 Too Many Requests response code instead.^[34] The phrase «Enhance your calm» comes from the 1993 movie Demolition Man, and its association with this number is likely a reference to cannabis.^{[citation needed]}

430 Request Header Fields Too Large (Shopify)

Used by Shopify, instead of the 429 Too Many Requests response code, when too many URLs are requested within a certain time frame.^[35]

450 Blocked by Windows Parental Controls (Microsoft)

The Microsoft extension code indicated when Windows Parental Controls are turned on and are blocking access to the requested webpage.^[36]

498 Invalid Token (Esri)

Returned by ArcGIS for Server. Code 498 indicates an expired or otherwise invalid token.^[37]

499 Token Required (Esri)

Returned by ArcGIS for Server. Code 499 indicates that a token is required but was not submitted.^[37]

509 Bandwidth Limit Exceeded (Apache Web Server/cPanel)

The server has exceeded the bandwidth specified by the server administrator; this is often used by shared hosting providers to limit the bandwidth of customers.^[38]

529 Site is overloaded

Used by Qualys in the SSLLabs server testing API to signal that the site can’t process the request.^[39]

530 Site is frozen

Used by the Pantheon Systems web platform to indicate a site that has been frozen due to inactivity.^[40]

598 (Informal convention) Network read timeout error

Used by some HTTP proxies to signal a network read timeout behind the proxy to a client in front of the proxy.^[41]

599 Network Connect Timeout Error

An error used by some HTTP proxies to signal a network connect timeout behind the proxy to a client in front of the proxy.

Internet Information Services

Microsoft’s Internet Information Services (IIS) web server expands the 4xx error space to signal errors with the client’s request.

440 Login Time-out

The client’s session has expired and must log in again.^[42]

449 Retry With

The server cannot honour the request because the user has not provided the required information.^[43]

451 Redirect

Used in Exchange ActiveSync when either a more efficient server is available or the server cannot access the users’ mailbox.^[44] The client is expected to re-run the HTTP AutoDiscover operation to find a more appropriate server.^[45]

IIS sometimes uses additional decimal sub-codes for more specific information,^[46] however these sub-codes only appear in the response payload and in documentation, not in the place of an actual HTTP status code.

nginx

The nginx web server software expands the 4xx error space to signal issues with the client’s request.^[47][48]

444 No Response

Used internally^[49] to instruct the server to return no information to the client and close the connection immediately.

494 Request header too large

Client sent too large request or too long header line.

495 SSL Certificate Error

An expansion of the 400 Bad Request response code, used when the client has provided an invalid client certificate.

496 SSL Certificate Required

An expansion of the 400 Bad Request response code, used when a client certificate is required but not provided.

497 HTTP Request Sent to HTTPS Port

An expansion of the 400 Bad Request response code, used when the client has made a HTTP request to a port listening for HTTPS requests.

499 Client Closed Request

Used when the client has closed the request before the server could send a response.

Cloudflare

Cloudflare’s reverse proxy service expands the 5xx series of errors space to signal issues with the origin server.^[50]

520 Web Server Returned an Unknown Error

The origin server returned an empty, unknown, or unexpected response to Cloudflare.^[51]

521 Web Server Is Down

The origin server refused connections from Cloudflare. Security solutions at the origin may be blocking legitimate connections from certain Cloudflare IP addresses.

522 Connection Timed Out

Cloudflare timed out contacting the origin server.

523 Origin Is Unreachable

Cloudflare could not reach the origin server; for example, if the DNS records for the origin server are incorrect or missing.

524 A Timeout Occurred

Cloudflare was able to complete a TCP connection to the origin server, but did not receive a timely HTTP response.

525 SSL Handshake Failed

Cloudflare could not negotiate a SSL/TLS handshake with the origin server.

526 Invalid SSL Certificate

Cloudflare could not validate the SSL certificate on the origin web server. Also used by Cloud Foundry’s gorouter.

527 Railgun Error

Error 527 indicates an interrupted connection between Cloudflare and the origin server’s Railgun server.^[52]

530

Error 530 is returned along with a 1xxx error.^[53]

AWS Elastic Load Balancer

Amazon’s Elastic Load Balancing adds a few custom return codes

460

Client closed the connection with the load balancer before the idle timeout period elapsed. Typically when client timeout is sooner than the Elastic Load Balancer’s timeout.^[54]

463

The load balancer received an X-Forwarded-For request header with more than 30 IP addresses.^[54]

561 Unauthorized

An error around authentication returned by a server registered with a load balancer. You configured a listener rule to authenticate users, but the identity provider (IdP) returned an error code when authenticating the user.^[55]

Caching warning codes (obsoleted)

The following caching related warning codes were specified under RFC 7234. Unlike the other status codes above, these were not sent as the response status in the HTTP protocol, but as part of the «Warning» HTTP header.^[56][57]

Since this «Warning» header is often neither sent by servers nor acknowledged by clients, this header and its codes were obsoleted by the HTTP Working Group in 2022 with RFC 9111.^[58]

110 Response is Stale

The response provided by a cache is stale (the content’s age exceeds a maximum age set by a Cache-Control header or heuristically chosen lifetime).

111 Revalidation Failed

The cache was unable to validate the response, due to an inability to reach the origin server.

112 Disconnected Operation

The cache is intentionally disconnected from the rest of the network.

113 Heuristic Expiration

The cache heuristically chose a freshness lifetime greater than 24 hours and the response’s age is greater than 24 hours.

199 Miscellaneous Warning

Arbitrary, non-specific warning. The warning text may be logged or presented to the user.

214 Transformation Applied

Added by a proxy if it applies any transformation to the representation, such as changing the content encoding, media type or the like.

299 Miscellaneous Persistent Warning

Same as 199, but indicating a persistent warning.

See also

• Custom error pages
• List of FTP server return codes
• List of HTTP header fields
• List of SMTP server return codes
• Common Log Format

Explanatory notes

References

External links

• «RFC 9110: HTTP Semantics and Content, Section 15 «Status Codes»«.
• Hypertext Transfer Protocol (HTTP) Status Code Registry

From Wikipedia, the free encyclopedia

This is a list of Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client’s request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the HTTP. The first digit of the status code specifies one of five standard classes of responses. The optional message phrases shown are typical, but any human-readable alternative may be provided, or none at all.

Unless otherwise stated, the status code is part of the HTTP standard (RFC 9110).

The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes.^[1]

All HTTP response status codes are separated into five classes or categories. The first digit of the status code defines the class of response, while the last two digits do not have any classifying or categorization role. There are five classes defined by the standard:

• 1xx informational response – the request was received, continuing process
• 2xx successful – the request was successfully received, understood, and accepted
• 3xx redirection – further action needs to be taken in order to complete the request
• 4xx client error – the request contains bad syntax or cannot be fulfilled
• 5xx server error – the server failed to fulfil an apparently valid request

1xx informational response

An informational response indicates that the request was received and understood. It is issued on a provisional basis while request processing continues. It alerts the client to wait for a final response. The message consists only of the status line and optional header fields, and is terminated by an empty line. As the HTTP/1.0 standard did not define any 1xx status codes, servers must not^{[note 1]} send a 1xx response to an HTTP/1.0 compliant client except under experimental conditions.

100 Continue

The server has received the request headers and the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). Sending a large request body to a server after a request has been rejected for inappropriate headers would be inefficient. To have a server check the request’s headers, a client must send Expect: 100-continue as a header in its initial request and receive a 100 Continue status code in response before sending the body. If the client receives an error code such as 403 (Forbidden) or 405 (Method Not Allowed) then it should not send the request’s body. The response 417 Expectation Failed indicates that the request should be repeated without the Expect header as it indicates that the server does not support expectations (this is the case, for example, of HTTP/1.0 servers).^[2]

101 Switching Protocols

The requester has asked the server to switch protocols and the server has agreed to do so.

102 Processing (WebDAV; RFC 2518)

A WebDAV request may contain many sub-requests involving file operations, requiring a long time to complete the request. This code indicates that the server has received and is processing the request, but no response is available yet.^[3] This prevents the client from timing out and assuming the request was lost.

103 Early Hints (RFC 8297)

Used to return some response headers before final HTTP message.^[4]

2xx success

This class of status codes indicates the action requested by the client was received, understood, and accepted.^[1]

200 OK

Standard response for successful HTTP requests. The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request, the response will contain an entity describing or containing the result of the action.

201 Created

The request has been fulfilled, resulting in the creation of a new resource.^[5]

202 Accepted

The request has been accepted for processing, but the processing has not been completed. The request might or might not be eventually acted upon, and may be disallowed when processing occurs.

203 Non-Authoritative Information (since HTTP/1.1)

The server is a transforming proxy (e.g. a Web accelerator) that received a 200 OK from its origin, but is returning a modified version of the origin’s response.^[6][7]

204 No Content

The server successfully processed the request, and is not returning any content.

205 Reset Content

The server successfully processed the request, asks that the requester reset its document view, and is not returning any content.

206 Partial Content

The server is delivering only part of the resource (byte serving) due to a range header sent by the client. The range header is used by HTTP clients to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.

207 Multi-Status (WebDAV; RFC 4918)

The message body that follows is by default an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.^[8]

208 Already Reported (WebDAV; RFC 5842)

The members of a DAV binding have already been enumerated in a preceding part of the (multistatus) response, and are not being included again.

226 IM Used (RFC 3229)

The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.^[9]

3xx redirection

This class of status code indicates the client must take additional action to complete the request. Many of these status codes are used in URL redirection.^[1]

A user agent may carry out the additional action with no user interaction only if the method used in the second request is GET or HEAD. A user agent may automatically redirect a request. A user agent should detect and intervene to prevent cyclical redirects.^[10]

300 Multiple Choices

Indicates multiple options for the resource from which the client may choose (via agent-driven content negotiation). For example, this code could be used to present multiple video format options, to list files with different filename extensions, or to suggest word-sense disambiguation.

301 Moved Permanently

This and all future requests should be directed to the given URI.

302 Found (Previously «Moved temporarily»)

Tells the client to look at (browse to) another URL. The HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect with the same method (the original describing phrase was «Moved Temporarily»),^[11] but popular browsers implemented 302 redirects by changing the method to GET. Therefore, HTTP/1.1 added status codes 303 and 307 to distinguish between the two behaviours.^[10]

303 See Other (since HTTP/1.1)

The response to the request can be found under another URI using the GET method. When received in response to a POST (or PUT/DELETE), the client should presume that the server has received the data and should issue a new GET request to the given URI.

304 Not Modified

Indicates that the resource has not been modified since the version specified by the request headers If-Modified-Since or If-None-Match. In such case, there is no need to retransmit the resource since the client still has a previously-downloaded copy.

305 Use Proxy (since HTTP/1.1)

The requested resource is available only through a proxy, the address for which is provided in the response. For security reasons, many HTTP clients (such as Mozilla Firefox and Internet Explorer) do not obey this status code.

306 Switch Proxy

No longer used. Originally meant «Subsequent requests should use the specified proxy.»

307 Temporary Redirect (since HTTP/1.1)

In this case, the request should be repeated with another URI; however, future requests should still use the original URI. In contrast to how 302 was historically implemented, the request method is not allowed to be changed when reissuing the original request. For example, a POST request should be repeated using another POST request.

308 Permanent Redirect

This and all future requests should be directed to the given URI. 308 parallel the behaviour of 301, but does not allow the HTTP method to change. So, for example, submitting a form to a permanently redirected resource may continue smoothly.

4xx client errors

This class of status code is intended for situations in which the error seems to have been caused by the client. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents should display any included entity to the user.

400 Bad Request

The server cannot or will not process the request due to an apparent client error (e.g., malformed request syntax, size too large, invalid request message framing, or deceptive request routing).

401 Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource. See Basic access authentication and Digest access authentication. 401 semantically means «unauthorised», the user does not have valid authentication credentials for the target resource.

Some sites incorrectly issue HTTP 401 when an IP address is banned from the website (usually the website domain) and that specific address is refused permission to access a website.^{[citation needed]}

402 Payment Required

Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, as proposed, for example, by GNU Taler,^[13] but that has not yet happened, and this code is not widely used. Google Developers API uses this status if a particular developer has exceeded the daily limit on requests.^[14] Sipgate uses this code if an account does not have sufficient funds to start a call.^[15] Shopify uses this code when the store has not paid their fees and is temporarily disabled.^[16] Stripe uses this code for failed payments where parameters were correct, for example blocked fraudulent payments.^[17]

403 Forbidden

The request contained valid data and was understood by the server, but the server is refusing action. This may be due to the user not having the necessary permissions for a resource or needing an account of some sort, or attempting a prohibited action (e.g. creating a duplicate record where only one is allowed). This code is also typically used if the request provided authentication by answering the WWW-Authenticate header field challenge, but the server did not accept that authentication. The request should not be repeated.

404 Not Found

The requested resource could not be found but may be available in the future. Subsequent requests by the client are permissible.

405 Method Not Allowed

A request method is not supported for the requested resource; for example, a GET request on a form that requires data to be presented via POST, or a PUT request on a read-only resource.

406 Not Acceptable

The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request. See Content negotiation.

407 Proxy Authentication Required

The client must first authenticate itself with the proxy.

408 Request Timeout

The server timed out waiting for the request. According to HTTP specifications: «The client did not produce a request within the time that the server was prepared to wait. The client MAY repeat the request without modifications at any later time.»

409 Conflict

Indicates that the request could not be processed because of conflict in the current state of the resource, such as an edit conflict between multiple simultaneous updates.

410 Gone

Indicates that the resource requested was previously in use but is no longer available and will not be available again. This should be used when a resource has been intentionally removed and the resource should be purged. Upon receiving a 410 status code, the client should not request the resource in the future. Clients such as search engines should remove the resource from their indices. Most use cases do not require clients and search engines to purge the resource, and a «404 Not Found» may be used instead.

411 Length Required

The request did not specify the length of its content, which is required by the requested resource.

412 Precondition Failed

The server does not meet one of the preconditions that the requester put on the request header fields.

413 Payload Too Large

The request is larger than the server is willing or able to process. Previously called «Request Entity Too Large» in RFC 2616.^[18]

414 URI Too Long

The URI provided was too long for the server to process. Often the result of too much data being encoded as a query-string of a GET request, in which case it should be converted to a POST request. Called «Request-URI Too Long» previously in RFC 2616.^[19]

415 Unsupported Media Type

The request entity has a media type which the server or resource does not support. For example, the client uploads an image as image/svg+xml, but the server requires that images use a different format.

416 Range Not Satisfiable

The client has asked for a portion of the file (byte serving), but the server cannot supply that portion. For example, if the client asked for a part of the file that lies beyond the end of the file. Called «Requested Range Not Satisfiable» previously RFC 2616.^[20]

417 Expectation Failed

The server cannot meet the requirements of the Expect request-header field.^[21]

418 I’m a teapot (RFC 2324, RFC 7168)

This code was defined in 1998 as one of the traditional IETF April Fools’ jokes, in RFC 2324, Hyper Text Coffee Pot Control Protocol, and is not expected to be implemented by actual HTTP servers. The RFC specifies this code should be returned by teapots requested to brew coffee.^[22] This HTTP status is used as an Easter egg in some websites, such as Google.com’s «I’m a teapot» easter egg.^[23][24][25] Sometimes, this status code is also used as a response to a blocked request, instead of the more appropriate 403 Forbidden.^[26][27]

421 Misdirected Request

The request was directed at a server that is not able to produce a response (for example because of connection reuse).

422 Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors.^[8]

423 Locked (WebDAV; RFC 4918)

The resource that is being accessed is locked.^[8]

424 Failed Dependency (WebDAV; RFC 4918)

The request failed because it depended on another request and that request failed (e.g., a PROPPATCH).^[8]

425 Too Early (RFC 8470)

Indicates that the server is unwilling to risk processing a request that might be replayed.

426 Upgrade Required

The client should switch to a different protocol such as TLS/1.3, given in the Upgrade header field.

428 Precondition Required (RFC 6585)

The origin server requires the request to be conditional. Intended to prevent the ‘lost update’ problem, where a client GETs a resource’s state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.^[28]

429 Too Many Requests (RFC 6585)

The user has sent too many requests in a given amount of time. Intended for use with rate-limiting schemes.^[28]

431 Request Header Fields Too Large (RFC 6585)

The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.^[28]

451 Unavailable For Legal Reasons (RFC 7725)

A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.^[29] The code 451 was chosen as a reference to the novel Fahrenheit 451 (see the Acknowledgements in the RFC).

5xx server errors

The server failed to fulfil a request.

Response status codes beginning with the digit «5» indicate cases in which the server is aware that it has encountered an error or is otherwise incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and indicate whether it is a temporary or permanent condition. Likewise, user agents should display any included entity to the user. These response codes are applicable to any request method.

500 Internal Server Error

A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.

501 Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request. Usually this implies future availability (e.g., a new feature of a web-service API).

502 Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

503 Service Unavailable

The server cannot handle the request (because it is overloaded or down for maintenance). Generally, this is a temporary state.^[30]

504 Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

505 HTTP Version Not Supported

The server does not support the HTTP version used in the request.

506 Variant Also Negotiates (RFC 2295)

Transparent content negotiation for the request results in a circular reference.^[31]

507 Insufficient Storage (WebDAV; RFC 4918)

The server is unable to store the representation needed to complete the request.^[8]

508 Loop Detected (WebDAV; RFC 5842)

The server detected an infinite loop while processing the request (sent instead of 208 Already Reported).

510 Not Extended (RFC 2774)

Further extensions to the request are required for the server to fulfill it.^[32]

511 Network Authentication Required (RFC 6585)

The client needs to authenticate to gain network access. Intended for use by intercepting proxies used to control access to the network (e.g., «captive portals» used to require agreement to Terms of Service before granting full Internet access via a Wi-Fi hotspot).^[28]

Unofficial codes

The following codes are not specified by any standard.

419 Page Expired (Laravel Framework)

Used by the Laravel Framework when a CSRF Token is missing or expired.

420 Method Failure (Spring Framework)

A deprecated response used by the Spring Framework when a method has failed.^[33]

420 Enhance Your Calm (Twitter)

Returned by version 1 of the Twitter Search and Trends API when the client is being rate limited; versions 1.1 and later use the 429 Too Many Requests response code instead.^[34] The phrase «Enhance your calm» comes from the 1993 movie Demolition Man, and its association with this number is likely a reference to cannabis.^{[citation needed]}

430 Request Header Fields Too Large (Shopify)

Used by Shopify, instead of the 429 Too Many Requests response code, when too many URLs are requested within a certain time frame.^[35]

450 Blocked by Windows Parental Controls (Microsoft)

The Microsoft extension code indicated when Windows Parental Controls are turned on and are blocking access to the requested webpage.^[36]

498 Invalid Token (Esri)

Returned by ArcGIS for Server. Code 498 indicates an expired or otherwise invalid token.^[37]

499 Token Required (Esri)

Returned by ArcGIS for Server. Code 499 indicates that a token is required but was not submitted.^[37]

509 Bandwidth Limit Exceeded (Apache Web Server/cPanel)

The server has exceeded the bandwidth specified by the server administrator; this is often used by shared hosting providers to limit the bandwidth of customers.^[38]

529 Site is overloaded

Used by Qualys in the SSLLabs server testing API to signal that the site can’t process the request.^[39]

530 Site is frozen

Used by the Pantheon Systems web platform to indicate a site that has been frozen due to inactivity.^[40]

598 (Informal convention) Network read timeout error

Used by some HTTP proxies to signal a network read timeout behind the proxy to a client in front of the proxy.^[41]

599 Network Connect Timeout Error

An error used by some HTTP proxies to signal a network connect timeout behind the proxy to a client in front of the proxy.

Internet Information Services

Microsoft’s Internet Information Services (IIS) web server expands the 4xx error space to signal errors with the client’s request.

440 Login Time-out

The client’s session has expired and must log in again.^[42]

449 Retry With

The server cannot honour the request because the user has not provided the required information.^[43]

451 Redirect

Used in Exchange ActiveSync when either a more efficient server is available or the server cannot access the users’ mailbox.^[44] The client is expected to re-run the HTTP AutoDiscover operation to find a more appropriate server.^[45]

IIS sometimes uses additional decimal sub-codes for more specific information,^[46] however these sub-codes only appear in the response payload and in documentation, not in the place of an actual HTTP status code.

nginx

The nginx web server software expands the 4xx error space to signal issues with the client’s request.^[47][48]

444 No Response

Used internally^[49] to instruct the server to return no information to the client and close the connection immediately.

494 Request header too large

Client sent too large request or too long header line.

495 SSL Certificate Error

An expansion of the 400 Bad Request response code, used when the client has provided an invalid client certificate.

496 SSL Certificate Required

An expansion of the 400 Bad Request response code, used when a client certificate is required but not provided.

497 HTTP Request Sent to HTTPS Port

An expansion of the 400 Bad Request response code, used when the client has made a HTTP request to a port listening for HTTPS requests.

499 Client Closed Request

Used when the client has closed the request before the server could send a response.

Cloudflare

Cloudflare’s reverse proxy service expands the 5xx series of errors space to signal issues with the origin server.^[50]

520 Web Server Returned an Unknown Error

The origin server returned an empty, unknown, or unexpected response to Cloudflare.^[51]

521 Web Server Is Down

The origin server refused connections from Cloudflare. Security solutions at the origin may be blocking legitimate connections from certain Cloudflare IP addresses.

522 Connection Timed Out

Cloudflare timed out contacting the origin server.

523 Origin Is Unreachable

Cloudflare could not reach the origin server; for example, if the DNS records for the origin server are incorrect or missing.

524 A Timeout Occurred

Cloudflare was able to complete a TCP connection to the origin server, but did not receive a timely HTTP response.

525 SSL Handshake Failed

Cloudflare could not negotiate a SSL/TLS handshake with the origin server.

526 Invalid SSL Certificate

Cloudflare could not validate the SSL certificate on the origin web server. Also used by Cloud Foundry’s gorouter.

527 Railgun Error

Error 527 indicates an interrupted connection between Cloudflare and the origin server’s Railgun server.^[52]

530

Error 530 is returned along with a 1xxx error.^[53]

AWS Elastic Load Balancer

Amazon’s Elastic Load Balancing adds a few custom return codes

460

Client closed the connection with the load balancer before the idle timeout period elapsed. Typically when client timeout is sooner than the Elastic Load Balancer’s timeout.^[54]

463

The load balancer received an X-Forwarded-For request header with more than 30 IP addresses.^[54]

561 Unauthorized

An error around authentication returned by a server registered with a load balancer. You configured a listener rule to authenticate users, but the identity provider (IdP) returned an error code when authenticating the user.^[55]

Caching warning codes (obsoleted)

The following caching related warning codes were specified under RFC 7234. Unlike the other status codes above, these were not sent as the response status in the HTTP protocol, but as part of the «Warning» HTTP header.^[56][57]

Since this «Warning» header is often neither sent by servers nor acknowledged by clients, this header and its codes were obsoleted by the HTTP Working Group in 2022 with RFC 9111.^[58]

110 Response is Stale

The response provided by a cache is stale (the content’s age exceeds a maximum age set by a Cache-Control header or heuristically chosen lifetime).

111 Revalidation Failed

The cache was unable to validate the response, due to an inability to reach the origin server.

112 Disconnected Operation

The cache is intentionally disconnected from the rest of the network.

113 Heuristic Expiration

The cache heuristically chose a freshness lifetime greater than 24 hours and the response’s age is greater than 24 hours.

199 Miscellaneous Warning

Arbitrary, non-specific warning. The warning text may be logged or presented to the user.

214 Transformation Applied

Added by a proxy if it applies any transformation to the representation, such as changing the content encoding, media type or the like.

299 Miscellaneous Persistent Warning

Same as 199, but indicating a persistent warning.

See also

• Custom error pages
• List of FTP server return codes
• List of HTTP header fields
• List of SMTP server return codes
• Common Log Format

Explanatory notes

References

External links

• «RFC 9110: HTTP Semantics and Content, Section 15 «Status Codes»«.
• Hypertext Transfer Protocol (HTTP) Status Code Registry

From Wikipedia, the free encyclopedia

This is a list of Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client’s request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the HTTP. The first digit of the status code specifies one of five standard classes of responses. The optional message phrases shown are typical, but any human-readable alternative may be provided, or none at all.

Unless otherwise stated, the status code is part of the HTTP standard (RFC 9110).

The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes.^[1]

All HTTP response status codes are separated into five classes or categories. The first digit of the status code defines the class of response, while the last two digits do not have any classifying or categorization role. There are five classes defined by the standard:

• 1xx informational response – the request was received, continuing process
• 2xx successful – the request was successfully received, understood, and accepted
• 3xx redirection – further action needs to be taken in order to complete the request
• 4xx client error – the request contains bad syntax or cannot be fulfilled
• 5xx server error – the server failed to fulfil an apparently valid request

1xx informational response

An informational response indicates that the request was received and understood. It is issued on a provisional basis while request processing continues. It alerts the client to wait for a final response. The message consists only of the status line and optional header fields, and is terminated by an empty line. As the HTTP/1.0 standard did not define any 1xx status codes, servers must not^{[note 1]} send a 1xx response to an HTTP/1.0 compliant client except under experimental conditions.

100 Continue

The server has received the request headers and the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). Sending a large request body to a server after a request has been rejected for inappropriate headers would be inefficient. To have a server check the request’s headers, a client must send Expect: 100-continue as a header in its initial request and receive a 100 Continue status code in response before sending the body. If the client receives an error code such as 403 (Forbidden) or 405 (Method Not Allowed) then it should not send the request’s body. The response 417 Expectation Failed indicates that the request should be repeated without the Expect header as it indicates that the server does not support expectations (this is the case, for example, of HTTP/1.0 servers).^[2]

101 Switching Protocols

The requester has asked the server to switch protocols and the server has agreed to do so.

102 Processing (WebDAV; RFC 2518)

A WebDAV request may contain many sub-requests involving file operations, requiring a long time to complete the request. This code indicates that the server has received and is processing the request, but no response is available yet.^[3] This prevents the client from timing out and assuming the request was lost.

103 Early Hints (RFC 8297)

Used to return some response headers before final HTTP message.^[4]

2xx success

This class of status codes indicates the action requested by the client was received, understood, and accepted.^[1]

200 OK

Standard response for successful HTTP requests. The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request, the response will contain an entity describing or containing the result of the action.

201 Created

The request has been fulfilled, resulting in the creation of a new resource.^[5]

202 Accepted

The request has been accepted for processing, but the processing has not been completed. The request might or might not be eventually acted upon, and may be disallowed when processing occurs.

203 Non-Authoritative Information (since HTTP/1.1)

The server is a transforming proxy (e.g. a Web accelerator) that received a 200 OK from its origin, but is returning a modified version of the origin’s response.^[6][7]

204 No Content

The server successfully processed the request, and is not returning any content.

205 Reset Content

The server successfully processed the request, asks that the requester reset its document view, and is not returning any content.

206 Partial Content

The server is delivering only part of the resource (byte serving) due to a range header sent by the client. The range header is used by HTTP clients to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.

207 Multi-Status (WebDAV; RFC 4918)

The message body that follows is by default an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.^[8]

208 Already Reported (WebDAV; RFC 5842)

The members of a DAV binding have already been enumerated in a preceding part of the (multistatus) response, and are not being included again.

226 IM Used (RFC 3229)

The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.^[9]

3xx redirection

This class of status code indicates the client must take additional action to complete the request. Many of these status codes are used in URL redirection.^[1]

A user agent may carry out the additional action with no user interaction only if the method used in the second request is GET or HEAD. A user agent may automatically redirect a request. A user agent should detect and intervene to prevent cyclical redirects.^[10]

300 Multiple Choices

Indicates multiple options for the resource from which the client may choose (via agent-driven content negotiation). For example, this code could be used to present multiple video format options, to list files with different filename extensions, or to suggest word-sense disambiguation.

301 Moved Permanently

This and all future requests should be directed to the given URI.

302 Found (Previously «Moved temporarily»)

Tells the client to look at (browse to) another URL. The HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect with the same method (the original describing phrase was «Moved Temporarily»),^[11] but popular browsers implemented 302 redirects by changing the method to GET. Therefore, HTTP/1.1 added status codes 303 and 307 to distinguish between the two behaviours.^[10]

303 See Other (since HTTP/1.1)

The response to the request can be found under another URI using the GET method. When received in response to a POST (or PUT/DELETE), the client should presume that the server has received the data and should issue a new GET request to the given URI.

304 Not Modified

Indicates that the resource has not been modified since the version specified by the request headers If-Modified-Since or If-None-Match. In such case, there is no need to retransmit the resource since the client still has a previously-downloaded copy.

305 Use Proxy (since HTTP/1.1)

The requested resource is available only through a proxy, the address for which is provided in the response. For security reasons, many HTTP clients (such as Mozilla Firefox and Internet Explorer) do not obey this status code.

306 Switch Proxy

No longer used. Originally meant «Subsequent requests should use the specified proxy.»

307 Temporary Redirect (since HTTP/1.1)

In this case, the request should be repeated with another URI; however, future requests should still use the original URI. In contrast to how 302 was historically implemented, the request method is not allowed to be changed when reissuing the original request. For example, a POST request should be repeated using another POST request.

308 Permanent Redirect

This and all future requests should be directed to the given URI. 308 parallel the behaviour of 301, but does not allow the HTTP method to change. So, for example, submitting a form to a permanently redirected resource may continue smoothly.

4xx client errors

This class of status code is intended for situations in which the error seems to have been caused by the client. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents should display any included entity to the user.

400 Bad Request

The server cannot or will not process the request due to an apparent client error (e.g., malformed request syntax, size too large, invalid request message framing, or deceptive request routing).

401 Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource. See Basic access authentication and Digest access authentication. 401 semantically means «unauthorised», the user does not have valid authentication credentials for the target resource.

Some sites incorrectly issue HTTP 401 when an IP address is banned from the website (usually the website domain) and that specific address is refused permission to access a website.^{[citation needed]}

402 Payment Required

Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, as proposed, for example, by GNU Taler,^[13] but that has not yet happened, and this code is not widely used. Google Developers API uses this status if a particular developer has exceeded the daily limit on requests.^[14] Sipgate uses this code if an account does not have sufficient funds to start a call.^[15] Shopify uses this code when the store has not paid their fees and is temporarily disabled.^[16] Stripe uses this code for failed payments where parameters were correct, for example blocked fraudulent payments.^[17]

403 Forbidden

The request contained valid data and was understood by the server, but the server is refusing action. This may be due to the user not having the necessary permissions for a resource or needing an account of some sort, or attempting a prohibited action (e.g. creating a duplicate record where only one is allowed). This code is also typically used if the request provided authentication by answering the WWW-Authenticate header field challenge, but the server did not accept that authentication. The request should not be repeated.

404 Not Found

The requested resource could not be found but may be available in the future. Subsequent requests by the client are permissible.

405 Method Not Allowed

A request method is not supported for the requested resource; for example, a GET request on a form that requires data to be presented via POST, or a PUT request on a read-only resource.

406 Not Acceptable

The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request. See Content negotiation.

407 Proxy Authentication Required

The client must first authenticate itself with the proxy.

408 Request Timeout

The server timed out waiting for the request. According to HTTP specifications: «The client did not produce a request within the time that the server was prepared to wait. The client MAY repeat the request without modifications at any later time.»

409 Conflict

Indicates that the request could not be processed because of conflict in the current state of the resource, such as an edit conflict between multiple simultaneous updates.

410 Gone

Indicates that the resource requested was previously in use but is no longer available and will not be available again. This should be used when a resource has been intentionally removed and the resource should be purged. Upon receiving a 410 status code, the client should not request the resource in the future. Clients such as search engines should remove the resource from their indices. Most use cases do not require clients and search engines to purge the resource, and a «404 Not Found» may be used instead.

411 Length Required

The request did not specify the length of its content, which is required by the requested resource.

412 Precondition Failed

The server does not meet one of the preconditions that the requester put on the request header fields.

413 Payload Too Large

The request is larger than the server is willing or able to process. Previously called «Request Entity Too Large» in RFC 2616.^[18]

414 URI Too Long

The URI provided was too long for the server to process. Often the result of too much data being encoded as a query-string of a GET request, in which case it should be converted to a POST request. Called «Request-URI Too Long» previously in RFC 2616.^[19]

415 Unsupported Media Type

The request entity has a media type which the server or resource does not support. For example, the client uploads an image as image/svg+xml, but the server requires that images use a different format.

416 Range Not Satisfiable

The client has asked for a portion of the file (byte serving), but the server cannot supply that portion. For example, if the client asked for a part of the file that lies beyond the end of the file. Called «Requested Range Not Satisfiable» previously RFC 2616.^[20]

417 Expectation Failed

The server cannot meet the requirements of the Expect request-header field.^[21]

418 I’m a teapot (RFC 2324, RFC 7168)

This code was defined in 1998 as one of the traditional IETF April Fools’ jokes, in RFC 2324, Hyper Text Coffee Pot Control Protocol, and is not expected to be implemented by actual HTTP servers. The RFC specifies this code should be returned by teapots requested to brew coffee.^[22] This HTTP status is used as an Easter egg in some websites, such as Google.com’s «I’m a teapot» easter egg.^[23][24][25] Sometimes, this status code is also used as a response to a blocked request, instead of the more appropriate 403 Forbidden.^[26][27]

421 Misdirected Request

The request was directed at a server that is not able to produce a response (for example because of connection reuse).

422 Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors.^[8]

423 Locked (WebDAV; RFC 4918)

The resource that is being accessed is locked.^[8]

424 Failed Dependency (WebDAV; RFC 4918)

The request failed because it depended on another request and that request failed (e.g., a PROPPATCH).^[8]

425 Too Early (RFC 8470)

Indicates that the server is unwilling to risk processing a request that might be replayed.

426 Upgrade Required

The client should switch to a different protocol such as TLS/1.3, given in the Upgrade header field.

428 Precondition Required (RFC 6585)

The origin server requires the request to be conditional. Intended to prevent the ‘lost update’ problem, where a client GETs a resource’s state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.^[28]

429 Too Many Requests (RFC 6585)

The user has sent too many requests in a given amount of time. Intended for use with rate-limiting schemes.^[28]

431 Request Header Fields Too Large (RFC 6585)

The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.^[28]

451 Unavailable For Legal Reasons (RFC 7725)

A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.^[29] The code 451 was chosen as a reference to the novel Fahrenheit 451 (see the Acknowledgements in the RFC).

5xx server errors

The server failed to fulfil a request.

Response status codes beginning with the digit «5» indicate cases in which the server is aware that it has encountered an error or is otherwise incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and indicate whether it is a temporary or permanent condition. Likewise, user agents should display any included entity to the user. These response codes are applicable to any request method.

500 Internal Server Error

A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.

501 Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request. Usually this implies future availability (e.g., a new feature of a web-service API).

502 Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

503 Service Unavailable

The server cannot handle the request (because it is overloaded or down for maintenance). Generally, this is a temporary state.^[30]

504 Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

505 HTTP Version Not Supported

The server does not support the HTTP version used in the request.

506 Variant Also Negotiates (RFC 2295)

Transparent content negotiation for the request results in a circular reference.^[31]

507 Insufficient Storage (WebDAV; RFC 4918)

The server is unable to store the representation needed to complete the request.^[8]

508 Loop Detected (WebDAV; RFC 5842)

The server detected an infinite loop while processing the request (sent instead of 208 Already Reported).

510 Not Extended (RFC 2774)

Further extensions to the request are required for the server to fulfill it.^[32]

511 Network Authentication Required (RFC 6585)

The client needs to authenticate to gain network access. Intended for use by intercepting proxies used to control access to the network (e.g., «captive portals» used to require agreement to Terms of Service before granting full Internet access via a Wi-Fi hotspot).^[28]

Unofficial codes

The following codes are not specified by any standard.

419 Page Expired (Laravel Framework)

Used by the Laravel Framework when a CSRF Token is missing or expired.

420 Method Failure (Spring Framework)

A deprecated response used by the Spring Framework when a method has failed.^[33]

420 Enhance Your Calm (Twitter)

Returned by version 1 of the Twitter Search and Trends API when the client is being rate limited; versions 1.1 and later use the 429 Too Many Requests response code instead.^[34] The phrase «Enhance your calm» comes from the 1993 movie Demolition Man, and its association with this number is likely a reference to cannabis.^{[citation needed]}

430 Request Header Fields Too Large (Shopify)

Used by Shopify, instead of the 429 Too Many Requests response code, when too many URLs are requested within a certain time frame.^[35]

450 Blocked by Windows Parental Controls (Microsoft)

The Microsoft extension code indicated when Windows Parental Controls are turned on and are blocking access to the requested webpage.^[36]

498 Invalid Token (Esri)

Returned by ArcGIS for Server. Code 498 indicates an expired or otherwise invalid token.^[37]

499 Token Required (Esri)

Returned by ArcGIS for Server. Code 499 indicates that a token is required but was not submitted.^[37]

509 Bandwidth Limit Exceeded (Apache Web Server/cPanel)

The server has exceeded the bandwidth specified by the server administrator; this is often used by shared hosting providers to limit the bandwidth of customers.^[38]

529 Site is overloaded

Used by Qualys in the SSLLabs server testing API to signal that the site can’t process the request.^[39]

530 Site is frozen

Used by the Pantheon Systems web platform to indicate a site that has been frozen due to inactivity.^[40]

598 (Informal convention) Network read timeout error

Used by some HTTP proxies to signal a network read timeout behind the proxy to a client in front of the proxy.^[41]

599 Network Connect Timeout Error

An error used by some HTTP proxies to signal a network connect timeout behind the proxy to a client in front of the proxy.

Internet Information Services

Microsoft’s Internet Information Services (IIS) web server expands the 4xx error space to signal errors with the client’s request.

440 Login Time-out

The client’s session has expired and must log in again.^[42]

449 Retry With

The server cannot honour the request because the user has not provided the required information.^[43]

451 Redirect

Used in Exchange ActiveSync when either a more efficient server is available or the server cannot access the users’ mailbox.^[44] The client is expected to re-run the HTTP AutoDiscover operation to find a more appropriate server.^[45]

IIS sometimes uses additional decimal sub-codes for more specific information,^[46] however these sub-codes only appear in the response payload and in documentation, not in the place of an actual HTTP status code.

nginx

The nginx web server software expands the 4xx error space to signal issues with the client’s request.^[47][48]

444 No Response

Used internally^[49] to instruct the server to return no information to the client and close the connection immediately.

494 Request header too large

Client sent too large request or too long header line.

495 SSL Certificate Error

An expansion of the 400 Bad Request response code, used when the client has provided an invalid client certificate.

496 SSL Certificate Required

An expansion of the 400 Bad Request response code, used when a client certificate is required but not provided.

497 HTTP Request Sent to HTTPS Port

An expansion of the 400 Bad Request response code, used when the client has made a HTTP request to a port listening for HTTPS requests.

499 Client Closed Request

Used when the client has closed the request before the server could send a response.

Cloudflare

Cloudflare’s reverse proxy service expands the 5xx series of errors space to signal issues with the origin server.^[50]

520 Web Server Returned an Unknown Error

The origin server returned an empty, unknown, or unexpected response to Cloudflare.^[51]

521 Web Server Is Down

The origin server refused connections from Cloudflare. Security solutions at the origin may be blocking legitimate connections from certain Cloudflare IP addresses.

522 Connection Timed Out

Cloudflare timed out contacting the origin server.

523 Origin Is Unreachable

Cloudflare could not reach the origin server; for example, if the DNS records for the origin server are incorrect or missing.

524 A Timeout Occurred

Cloudflare was able to complete a TCP connection to the origin server, but did not receive a timely HTTP response.

525 SSL Handshake Failed

Cloudflare could not negotiate a SSL/TLS handshake with the origin server.

526 Invalid SSL Certificate

Cloudflare could not validate the SSL certificate on the origin web server. Also used by Cloud Foundry’s gorouter.

527 Railgun Error

Error 527 indicates an interrupted connection between Cloudflare and the origin server’s Railgun server.^[52]

530

Error 530 is returned along with a 1xxx error.^[53]

AWS Elastic Load Balancer

Amazon’s Elastic Load Balancing adds a few custom return codes

460

Client closed the connection with the load balancer before the idle timeout period elapsed. Typically when client timeout is sooner than the Elastic Load Balancer’s timeout.^[54]

463

The load balancer received an X-Forwarded-For request header with more than 30 IP addresses.^[54]

561 Unauthorized

An error around authentication returned by a server registered with a load balancer. You configured a listener rule to authenticate users, but the identity provider (IdP) returned an error code when authenticating the user.^[55]

Caching warning codes (obsoleted)

The following caching related warning codes were specified under RFC 7234. Unlike the other status codes above, these were not sent as the response status in the HTTP protocol, but as part of the «Warning» HTTP header.^[56][57]

Since this «Warning» header is often neither sent by servers nor acknowledged by clients, this header and its codes were obsoleted by the HTTP Working Group in 2022 with RFC 9111.^[58]

110 Response is Stale

The response provided by a cache is stale (the content’s age exceeds a maximum age set by a Cache-Control header or heuristically chosen lifetime).

111 Revalidation Failed

The cache was unable to validate the response, due to an inability to reach the origin server.

112 Disconnected Operation

The cache is intentionally disconnected from the rest of the network.

113 Heuristic Expiration

The cache heuristically chose a freshness lifetime greater than 24 hours and the response’s age is greater than 24 hours.

199 Miscellaneous Warning

Arbitrary, non-specific warning. The warning text may be logged or presented to the user.

214 Transformation Applied

Added by a proxy if it applies any transformation to the representation, such as changing the content encoding, media type or the like.

299 Miscellaneous Persistent Warning

Same as 199, but indicating a persistent warning.

See also

• Custom error pages
• List of FTP server return codes
• List of HTTP header fields
• List of SMTP server return codes
• Common Log Format

Explanatory notes

References

External links

• «RFC 9110: HTTP Semantics and Content, Section 15 «Status Codes»«.
• Hypertext Transfer Protocol (HTTP) Status Code Registry

Многие пользователи при входе на какой нибудь сайт, под своим логином, или для регистрации, иногда сталкиваются с проблемой не возможностью этого сделать, из-за ошибки 423  (Method locked due to malicious activity from your IP address). Эта ошибка означает, что этот ip заблокирован хостером за аномальную активность, а именно интернет мошенничество. Так же вероятно, что это результат вируса на компьютере пользователя. Существуют и другие причины этой ошибки о которых пойдет речь в этой статье, а также как с этим можно бороться. 

 Как написано выше, эта ошика может возникнуть из-за вируса на компьютере, поэтому, первым делом проверьте вашу систему антивирусными утилитами на наличие таковых. Хороший вариант воспользоваться такими сканерами как Dr.Web CureIt или AdwCleaner.

 Зачастую, Error 423 (Method locked due to malicious activity from your IP address) происходит из-за Вашего динамического IP адреса, через который в сеть выходят тысячи пользователей.
Для решения этой ситуации необходимо приобрести статистический IP, или так называемый «белый адрес», который получить сейчас довольно таки сложно, так как провайдеры сидят на IPv4 и свободных адресов может и не быть, а если и есть, то стоят они гараздо дороже. В случае если у Вас нет возможности перейти на статистический IP адрес, есть вариант применить «исскуственный» способ смены IP адреса установив специальные программы дополнения в Ваш браузер. Очень хорошая программка для таких целей ZenMate. Эта дополнение сделана для браузеров Mozilla Firefox и Google Chrome. Включайте ZenMate по мере надобности, там где блокируется вход на нужный Вам сайт.

Со временем Error 423 может исчезнуть сама по себе, если причиной этой ошибки был Ваш интернет-провайдер. 

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