## HTTP Error Messages

The following standard HTTP Error Messages will be supported. Status codes starting with “4” indicate a client error in which the request contains bad syntax or cannot be fulfilled. Status codes starting with “5” indicate a server error in which the server failed to fulfill an apparently valid request.

Table 7: HTTP Error Messages
Status Code | Cause of Failure | Failure Message Displayed to the User/Resolution (“N/A”: Avaya IP Phone will never send the status code)
--- | --- | ---
400 | Bad Request | Due to incorrect syntax the server could not understand the request.
401 | Unauthorized | The request requires user authentication.
402 | Payment Required | N/A
403 | Forbidden | The server has indicated it will not respond to your query.
404 | Not Found | The server has not found anything matching the request.
405 | Method Not Allowed | N/A
406 | Not Acceptable | N/A
407 | Proxy Authentication Required | The request requires user authentication.
408 | Request Time-out | N/A
409 | Conflict | The request could not be completed due to a conflict with the current state of the resource.
410 | Gone | The requested resource is no longer available.
411 | Length Required | The server refuses to accept the request.
412 | Precondition Failed | N/A
413 | Request Entity Too Large | The server refuses to accept the request because the request entity is too large.
414 | Request-URI Too Large | The request-URI is longer than the server can interpret.
415 | Unsupported Media Type | The server refuses to accept the request because it's in an unsupported format.
416 | Requested range not satisfiable | N/A
417 | Expectation Failed | N/A
500 | Internal Server Error | The server encountered an unexpected condition that prevented it from fulfilling the request.
501 | Not Implemented | N/A
502 | Bad Gateway | The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to fulfill the request.
503 | Service Unavailable | The server is currently unable to handle the request due to a temporary overloading or maintenance of the server.
504 | Gateway Time-out | The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified.
505 | HTTP Version not supported | The server does not support, or refuses to support, the HTTP protocol version that was used in the request message.