HTTP CODES 400-417

400 - Bad Request
The syntax of the request was not understood by the server.

401 - Not Authorised
The request needs user authentication

402 - Payment Required
Reserved for future use.

403 - Forbidden
The server has refused to fulfill the request.

404 - Not Found
The document/file requested by the client was not found.

405 - Method Not Allowed
The method specified in the Request-Line is not allowed for the specified resource.

406 - Not Acceptable
The resource requested is only capable of generating response entities which have content characteristics not specified in the accept headers sent in the request.

407 - Proxy Authentication Required
The request first requires authentication with the proxy.

408 - Request Timeout
The client failed to sent a request in the time allowed by the server.

409 - Conflict
The request was unsuccessful due to a conflict in the state of the resource.

410 - Gone
The resource requested is no longer available and no forwarding address is available.

411 - Length Required
The server will not accept the request without a valid Content-Length header field.

412 - Precondition Failed
A precondition specified in one or more Request-Header fields returned false.

413 - Request Entity Too Large
The request was unsuccessful because the request entity is larger than the server will allow.

414 - Request URI Too Long
The request was unsuccessful because the URI specified is longer than the server is willing to process.

415 - Unsupported Media Type
The request was unsuccessful because the entity of the request is in a format not supported by the requested resource for the method requested.

416 - Requested Range Not Satisfiable
The request included a Range request-header field, and not any of the range-specifier values in this field overlap the current extent of the selected resource, and also the request did not include an If-Range request-header field.

417 - Expectation Failed
The expectation given in the Expect request-header could not be fulfilled by the server.