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HTTP status codes reference

Codes 3xx (redirection)

A list of HTTP status codes used for request redirection (codes 3xx).

CodeErrorDescription
300Multiple choice

The requested URL points to more than one resource, and the robot could not determine which page the URL refers to (code 300 Multiple Choices is received).

Correct the headers or specify the resource correctly, and then the robot will be able to index the page.

301Resource moved permanently

The server does not use this document any more, and the link redirects to another page (code 301 Moved Permanently is received).

As the users will not be able to see such documents, displaying them in search results makes no sense, and the robot does not index them. However the robot will surely index the page to which the redirection is set up.

302Resource moved temporarily

The requested resource has been temporarily moved to another address (code 302 Found is received).

As the users will not be able to see such documents, displaying them in search results makes no sense, and the robot does not index them. However the robot will surely index the page to which the redirection is set up.

303See another resource

The requested resource resides at another address and should be requested using GET method (code 303 See Other) is received). If you want the page in question to appear in the search, it must respond with code 200.

304Resource not modified

304 Not Modified code was returned. If your page has not changed since the last time the robot accessed your site, we recommend returning this code. This will speed up indexing and decrease traffic.

305Use proxy

Access to the requested resource is only possible through the proxy server specified in the Location header (code 305 Use Proxy is received).

307Temporary redirection

The requested resource has been temporarily moved to another address that should be registered in Location (code 307 Temporary Redirect) is received).

Codes 4xx (client error)

Contains a list of HTTP status codes that denote possible errors in client request (codes 4xx).

CodeErrorDescription
400Invalid request

The server cannot understand the request because of incorrect syntax (code 400 Bad Request is received).

401Unauthorized request

To access the document, one must enter a password or be a registered user (code 401 Unauthorized is received).

402Payment required for the query

Internal error or server configuration error (code 402 Payment Required is received).

403Access to resource forbidden

Access to the document is forbidden (code 403 Forbidden is received). If you want this page to be indexed, allow access to it.

404Resource not found

The document does not exist (code 404 Not Found is received). If you have deleted a certain section of the site, you can disallow the robot to access it, using robots.txt. If such page never existed at your site, please ignore the error. It is possible that someone published an incorrect link to your site.

405Method not allowed

The method specified in the Request-Line is not allowed for this resource, and the robot could not index the resource (code 405 Method Not Allowed is received).

406Unacceptable request

The requested document exists, but in another format (its language or encoding are not supported by the robot). Code 406 Not Acceptable is received.

407Firewall, proxy authentication required

Proxy server authentication is required (code 407 Proxy Authentication Required is received).

408Request timeout

The site did not transfer the complete request during the specified time, and the robot has terminated the connection (code 408 Request Timeout is received).

409Conflict

The request is in conflict with another request or with server configuration (code 409 Conflict is received).

410Resource unavailable

The requested resource was permanently deleted from the site (code 410 Gone is received).

411Length must be specified

The server rejects requests without a certain header, Content-Length (code 411 Length Required is received). Correct the headers on the server, and then the robot will be able to index the page next time.

412Precondition processing failure

In the course of processing one or more fields of the request header a discrepancy was discovered (a failure or error of precondition processing). Code 412 Precondition Failed is received.

413The body of the request is too long.

The server rejects the request because it is too long for the server to process (code 413 Request Entity Too Large is received).

414Unacceptable length of URI request

The server rejects the request because the URI requested by the robot (Request-URI) is too long for the server to process (code 414 Request-URI Too Long is received).

415Unsupported MIME type

The server rejects the request because the format of the request body is not supported (code 415 Unsupported Media Type is received).

416The range cannot be processed

The server rejects the request because the value of the Range field in the request header specifies an unacceptable range (code 416 Requested Range Not Satisfiable is received).

417Expectation failure

The server rejects the request because the value of the Expect field in the request header does not match expectation (code 417 Expectation Failed is received).

422Unprocessable entity

The server cannot process one or more request elements (code 422 Unprocessable Entity is received).

423Locked

The server rejects the request because one of the requested resources is locked (code 423 Locked is received).

424Invalid dependency

The server rejects the request because one of the requested resources is locked (code 424 Failed Dependency is received).

426Upgrade required

The server requests connection upgrade to SSL, but the client does not support SSL (code 426 Upgrade Required is received).

Codes 5xx (server error)

Contains a list of HTTP status codes that denote possible errors in server request (codes 5xx).

CodeErrorDescription
500Internal server error

The server encountered an unexpected condition that prevents it from fulfilling the request (code 500 Internal Server Error is received).

501Method not supported

The server does not support the features required to fulfill the request (code 501 Not Implemented is received). This response is returned in the situations when the server cannot recognize the request method and cannot provide it for any resource.

502Gateway error.

A server, acting as gateway or proxy, received unacceptable response from the next server in the request chain which it tried to access to fulfill the request (code 502 Bad Gateway is received).

503Service unavailable

An error occurred because of temporary overload or planned maintenance downtime of the server (code 503 Service Unavailable is received).

504Gateway timeout

A server, acting as external gateway or proxy, did not receive response from the next server further up in the request chain which it tried to access to fulfill the request (code 504 Gateway Timeout is received).

505HTTP version is not supported

The server does not support the version of the HTTP protocol used in the robot request message (code 505 HTTP Version Not Supported is received).

507Insufficient space

The server cannot process the request because there is not enough space on disk (code 507 Insufficient Storage is received).

510Extensions are missing

The server cannot process the request because the requested extension is not supported (code 510 Not Extended is received).

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