Http Unknown Error
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referer DNT X-Forwarded-For Status codes 301 Moved Permanently 302 Found 303 See Other 403 Forbidden 404 Not Found 451 Unavailable For Legal Reasons v t e This is a list of Hypertext Transfer Protocol (HTTP) response status codes. It includes codes from IETF http 418 internet standards, other IETF RFCs, other specifications, and some additional commonly used codes. The first
Http Response Example
digit of the status code specifies one of five classes of response; an HTTP client must recognise these five classes at a minimum. The
Http Status Codes Cheat Sheet
phrases used are the standard wordings, but any human-readable alternative can be provided. Unless otherwise stated, the status code is part of the HTTP/1.1 standard (RFC 7231).[1] The Internet Assigned Numbers Authority (IANA) maintains the official registry of
Http 422
HTTP status codes.[2] Microsoft IIS sometimes uses additional decimal sub-codes to provide more specific information,[3] but not all of those are here (note that these sub-codes only appear in the response payload and in documentation; not in the place of an actual HTTP status code). Contents 1 1xx Informational 2 2xx Success 3 3xx Redirection 4 4xx Client Error 5 5xx Server Error 6 Unofficial codes 6.1 Internet Information Services 6.2 nginx 6.3 Cloudflare 7 See also http code 403 8 Notes 9 References 10 External links 1xx Informational[edit] Request received, continuing process. This class of status code indicates a provisional response, consisting only of the Status-Line and optional headers, and is terminated by an empty line. Since HTTP/1.0 did not define any 1xx status codes, servers must not[note 1] send a 1xx response to an HTTP/1.0 client except under experimental conditions.[4] 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. The response 417 Expectation Failed indicates the request should not be continued.[2] 101 Switching Protocols The requester has asked the server to switch protocols and the server has agreed to do so.[5] 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.[6] This prev
What should I do if I'm expecting a surge or spike in traffic? My website is slow or having performance issues Why do my server logs show CloudFlare's IPs using CloudFlare? Cloudflare http code 302 Support Troubleshooting Error Pages > Error 520: Web server is returning an unknown error http 503 Error 520: Web server is returning an unknown error Michelle Zatlyn October 07, 2016 23:16 Overview The 520 error is essentially http 504 a “catch-all” response for when the origin server returns something unexpected or something that is not tolerated/interpreted (protocol violation or empty response). While the 520 error can be triggered by very unique and strange edge-case https://en.wikipedia.org/wiki/List_of_HTTP_status_codes scenarios, they are generally caused by: Connection resets (following a successful TCP handshake) Headers exceed CloudFlare’s header size limit (over 8kb) Empty response from origin Invalid HTTP response HTTP response missing response headers If any of these conditions above can be confirmed from the webserver hosting the site, then it is recommended to consult with the host provider for assistance with the webserver configuration to avoid further interruption and errors. https://support.cloudflare.com/hc/en-us/articles/200171936-Error-520-Web-server-is-returning-an-unknown-error Common Causes 520 errors are generally caused at Layer 7, which is the Application Layer. This means that a 520 error is the result of a bad response coming back from the application. Rate limiting, or filtering requests (e.g. by connecting IP, or volume/frequency) can sometime cause issues with your application. Troubleshooting Due to the nature of the 520 response, it is best to test against the origin server response using a cURL command to confirm if any conditions have been met to trigger the error. This especially true to determine if the origin server is returning an empty reply, invalid HTTP response, or extremely large response headers. Here is an example command used to force the Host HTTP header while sending the request to the source IP where the domain is hosted (in this example we are sending a request for a login page): curl -vso /dev/null --user-agent "Mozilla 5.0" -H "Host: example.com" http://123.123.123.321/login Here is an example output where the origin response is an empty reply, which would normally trigger a 520 error if the request was proxied by CloudFlare: * Hostname was NOT found in DNS cache* Trying 123.123.123.321...* Connected to 123.123.123.321 (123.123.123.321) port 80 (#0)> GET /login HTTP/1.1> User-Agent: Mozilla 5.0> Accept: */*> Host: ex
DocumentationBest PracticesAPI OverviewUpcoming changes to TweetsObject: UsersObject: TweetsObject: EntitiesObject: Entities in ObjectsObject: PlacesTwitter IDsConnecting to Twitter API using TLSUsing cursors to navigate collectionsError Codes & ResponsesTwitter LibrariesAPI StatusPlaybooksEventsCase StudiesManage My AppsTerms of UseError Codes & ResponsesHTTP Status CodesThe Twitter API attempts to return appropriate HTTP https://dev.twitter.com/overview/api/response-codes status codes for every request.CodeTextDescription200OKSuccess!304Not ModifiedThere was no new data to return.400Bad RequestThe request was invalid or cannot be otherwise served. An accompanying error message will explain further. In API v1.1, requests without authentication are considered invalid and will yield this response.401UnauthorizedAuthentication credentials were missing or incorrect.Also returned in other circumstances, for example all calls to API http code v1 endpoints now return 401 (use API v1.1 instead).403ForbiddenThe request is understood, but it has been refused or access is not allowed. An accompanying error message will explain why. This code is used when requests are being denied due to update limits. Other reasons for this status being returned are listed alongside the response codes in http unknown error the table below.404Not FoundThe URI requested is invalid or the resource requested, such as a user, does not exists. Also returned when the requested format is not supported by the requested method.406Not AcceptableReturned by the Search API when an invalid format is specified in the request.410GoneThis resource is gone. Used to indicate that an API endpoint has been turned off. For example: "The Twitter REST API v1 will soon stop functioning. Please migrate to API v1.1."420Enhance Your CalmReturned by the version 1 Search and Trends APIs when you are being rate limited.422Unprocessable EntityReturned when an image uploaded to POST account / update_profile_banner is unable to be processed.429Too Many RequestsReturned in API v1.1 when a request cannot be served due to the application's rate limit having been exhausted for the resource. See Rate Limiting in API v1.1.500Internal Server ErrorSomething is broken. Please post to the developer forums so the Twitter team can investigate.502Bad GatewayTwitter is down or being upgraded.503Service UnavailableThe Twitter servers are up, but overloaded with requests.