Let's see what does each of these numbers means.
Client Request Errors
400 - Bad Request
401 - Authorization Required
403 - Forbidden
404 - Not Found
405 - Method Not Allowed
406 - Not Acceptable (encoding)
407 - Proxy Authentication Required
408 - Request Timed Out
409 - Conflicting Request
410 - Gone
411 - Content Length Required
412 - Precondition Failed
413 - Request Entity Too Long
414 - Request URI Too Long
415 - Unsupported Media Type
Server Errors
500 - Internal Server Error
501 - Not Implemented
502 - Bad Gateway
503 - Service Unavailable
504 - Gateway Timeout
505 - HTTP Version Not Supported
Write by Arafa Daming
