4xx Client Error

    The request contains bad syntax or cannot be fulfilled.

• 400: Bad Request
• 401: Unauthorized
• Similar to 403/Forbidden, but specifically for use when authentication is possible but has failed or not yet been provided. See basic authentication scheme and digest access authentication.
• 402: Payment Required
• The original intention was that this code might be used as part of some form of digital cash/micropayment scheme, but that has never eventuated, and thus this code has never been used.
• 403: Forbidden
• 404: Not Found
• 405: Method Not Allowed
• 406: Not Acceptable
• 407: Proxy Authentication Required
• 408: Request Timeout
• 409: Conflict
• 410: Gone
• 411: Length Required
• 412: Precondition Failed
• 413: Request Entity Too Large
• 414: Request-URL Too Long
• 415: Unsupported Media Type
• 416: Requested Range Not Satisfiable
• 417: Expectation Failed
• 449: Retry With
• A Microsoft extension: The request should be retried after doing the appropriate action.