It is non-committal, meaning that there is no way in HTTP to later send an asynchronous response indicating the outcome of processing the request. There are many situations that could cause a web server to respond to a request with a particular error code--we will cover common potential causes and solutions. January 2002. Internet Information Services The Internet Information Services expands the 4xx error space to signal errors with the client's request. 440 Login Timeout The client's session has expired and must log in again. 449 Retry With The server cannot honour the request because the user has not provided the required information. 451 Redirect Used in Exchange ActiveSync when either a more efficient server is available or the server cannot access the users' mailbox. The client is expected to re-run the HTTP AutoDiscover operation to find a more appropriate server. nginx The nginx web server software expands the 4xx error space to signal issues with the client's request. These are only used for logging purposes, no actual response is sent with these codes. 444 No Response Used to indicate that the server has returned no information to the client and closed the connection. 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. navigate here
Transparent Content Negotiation in HTTP. Wikipedia The requested resource could not be found but may be available again in the future. Google Developers API uses this status if a particular developer has exceeded the daily limit on requests. 21.co Bitcoin micropayment service uses this status in response for every client http request. 403 Forbidden The request was a valid request, but the server is refusing to respond to it. The phrases used are the standard wordings, but any human-readable alternative can be provided. click for more info
The entity format is specified by the media type given in the Content- Type header field. Likewise, user agents should display any included entity to the user. Wikipedia A request was made of a resource using a request method not supported by that resource; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource. 406 Not Acceptable The resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headers sent in the request. If the request already included Authorization credentials, then the 401 response indicates that authorization has been refused for those credentials.
If the response is the result of an If-Range request that used a weak validator, the response MUST NOT include other entity-headers; this prevents inconsistencies between cached entity-bodies and updated headers. Google. 2014. Wikipedia This and all future requests should be directed to the given URI. 302 Found The requested resource resides temporarily under a different URI. Http Code 302 Note: Note to implementors: some deployed proxies are known to return 400 or 500 when DNS lookups time out.
The client SHOULD NOT repeat the request without modifications. Http Status Codes Cheat Sheet This response is primarily intended to allow input for actions to take place without causing a change to the user agent's active document view, although any new or updated metainformation SHOULD be applied to the document currently in the user agent's active view. This status code is commonly used when the server does not wish to reveal exactly why the request has been refused, or when no other response is applicable. https://en.wikipedia.org/wiki/List_of_HTTP_status_codes Usually, this is invisible, though I'm sure you've seen one of the very common Response codes - 404, indicating a page was not found.
Client Error 400 - Bad RequestA status code of 400 indicates that the server did not understand the request due to bad syntax.401 - UnauthorizedA 401 status code indicates that before a resource can be accessed, the client must be authorised by the server.402 - Payment RequiredThe 402 status code is not currently in use, being listed as "reserved for future use".403 - ForbiddenA 403 status code indicates that the client cannot access the requested resource. Http 422 Response body content may or may not be present. 202 Accepted The request has been accepted for processing, but the processing has not been completed. If the request method was not HEAD and the server wishes to make public why the request has not been fulfilled, it SHOULD describe the reason for the refusal in the entity. However, most existing user agent implementations treat 302 as if it were a 303 response, performing a GET on the Location field-value regardless of the original request method.
Otherwise (i.e., the conditional GET used a weak validator), the response MUST NOT include other entity-headers; this prevents inconsistencies between cached entity-bodies and updated headers. The entity format is specified by the media type given in the Content-Type header field. Http Error Wordpress The client MAY repeat the request without modifications at any later time. 10.4.10 409 Conflict The request could not be completed due to a conflict with the current state of the resource. Http Response Example Generally, this is a temporary state. 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 protocol version used in the request. 506 Variant Also Negotiates (RFC 2295) Transparent content negotiation for the request results in a circular reference. 507 Insufficient Storage (WebDAV; RFC 4918) The server is unable to store the representation needed to complete the request. 508 Loop Detected (WebDAV; RFC 5842) The server detected an infinite loop while processing the request (sent in lieu of 208 Already Reported). 510 Not Extended (RFC 2774) Further extensions to the request are required for the server to fulfill it. 511 Network Authentication Required (RFC 6585) The client needs to authenticate to gain network access.
A response received with a status code of 226 MAY be used by a cache, in conjunction with a cache entry for the base instance, to create a cache entry for the current instance. http://orgias.org/http-code/html-error-codes-200.html with a HTML form). It can be used both when the set of request header fields in total are too large, and when a single header field is at fault. The response MAY include new or updated metainformation in the form of entity-headers, which if present SHOULD be associated with the requested variant. Http Code 403
The server returns no information to the client and closes the connection (useful as a deterrent for malware). 449 Retry With (Microsoft) Wikipedia A Microsoft extension. The origin server MUST create the resource before returning the 201 status code. However, known implementations do exist. http://orgias.org/http-code/html-error-codes-400.html The client MAY repeat the request with a suitable Proxy-Authorization header field (section 14.34).
If no Retry-After is given, the client SHOULD handle the response as it would for a 500 response. Http 404 The response representation SHOULD contain a link to a resource that allows the user to submit credentials (e.g. The server should send back all the information necessary for the client to issue an extended request.
If the request already included Authorization credentials, then the 401 response indicates that authorization has been refused for those credentials. This is the appropriate response when the server does not recognize the request method and is not capable of supporting it for any resource. Wikipedia The server is unable to store the representation needed to complete the request. 508 Loop Detected (WebDAV) The 508 (Loop Detected) status code indicates that the server terminated an operation because it encountered an infinite loop while processing a request with "Depth: infinity". Http 502 In contrast to 302, the request method should not be changed when reissuing the original request.
If the client continues sending data to the server after the close, the server's TCP stack will send a reset packet to the client, which may erase the client's unacknowledged input buffers before they can be read and interpreted by the HTTP application. Retrieved 2016-10-12. The request MAY be resubmitted after reducing the size of the request header fields. http://orgias.org/http-code/html-web-error-codes.html Wikipedia The request was well-formed but was unable to be followed due to semantic errors. 423 Locked (WebDAV) The 423 (Locked) status code means the source or destination resource of a method is locked.
The RFC specifies this code should be returned by teapots requested to brew coffee. This HTTP status is used as an easter egg in some websites, including Google.com. 421 Misdirected Request (RFC 7540) The request was directed at a server that is not able to produce a response (for example because a connection reuse). 422 Unprocessable Entity (WebDAV; RFC 4918) The request was well-formed but was unable to be followed due to semantic errors. 423 Locked (WebDAV; RFC 4918) The resource that is being accessed is locked. 424 Failed Dependency (WebDAV; RFC 4918) The request failed due to failure of a previous request (e.g., a PROPPATCH). 426 Upgrade Required The client should switch to a different protocol such as TLS/1.0, given in the Upgrade header field. 428 Precondition Required (RFC 6585) The origin server requires the request to be conditional. Wikipedia No longer used. Generally, this is a temporary state. 504 Gateway Timeout The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI (e.g. For each binding to a collection inside the request's scope, only one will be reported with a 200 status, while subsequent DAV:response elements for all other bindings will use the 208 status, and no DAV:response elements for their descendants are included.
If you encounter any error codes that were not mentioned in this guide, or if you know of other likely solutions to the ones that were described, feel free to discuss them in the comments! Check Up Down. Successful creation occurred (via either POST or PUT). The request MUST have included an A-IM header field listing at least one instance-manipulation.
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 request, such as an edit conflict between multiple simultaneous updates. 410 Gone Indicates that the resource requested is no longer available and will not be available again. Wikipedia As a WebDAV request may contain many sub-requests involving file operations, it may take a long time to complete the request. The Location field gives the URI of the proxy. If the 301 status code is received in response to a request other than GET or HEAD, the user agent MUST NOT automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which the request was issued.
Redirection messages 300 Multiple Choice The request has more than one possible responses. Server error responses 500 Internal Server Error The server has encountered a situation it doesn't know how to handle. 501 Not Implemented The request method is not supported by the server and cannot be handled. The proxy MUST return a Proxy-Authenticate header field (section 14.33) containing a challenge applicable to the proxy for the requested resource. Wikipedia This class of status codes indicates the action requested by the client was received, understood, accepted and processed successfully. 200 OK The request has succeeded.
censorship or government-mandated blocked access.