HTTP status code when a client makes a request, WEB server returns a status response to the client, common HTTP status following five categories:
1. Information codes: 1xx,
2. success codes: 2xx,
3. Redirection: 3xx,
4. Client Error: 4xx,
5. Server Error: 5xx
Request Error 400: This code indicates that the server can not understand the request because the syntax is invalid. This is because the requests sent to the server with invalid syntax.
(Solution: syntax error checking HTTP request that may occur, to ensure that the requested URL or Post syntax error .. no later try clearing your browser's cookie cache and try again ..)
401 Unauthorized Error: The server requires authentication password to access the file or the requested resource.
(Solution: providing a username and / or password or server to provide the right.)
403 Forbidden: The server refused to give the correct response to the file access request.
(Solution: Agent can be resolved by modifying the contents, replace IP, etc.)
404 File not found: Unable to find the resources requested by the user.
(Solution: Is there a file request to query the directory.)
Common server-side HTTP error code -----------------------------
500 Internal Server Error: The most common cause is a server configuration error.
Error Gateway 502: server operable to acquire an invalid response obtained when processing the response (interfaces, databases, etc.) required to request another server.
503 Service Unavailable: The server for some other reason in maintenance or off
504 Gateway Timeout: When the response is obtained server acts as a gateway or proxy server and can not be specified period of time from the proxy server, you will receive this error.