Common HTTP error codes

Apache error codes are something that we come accross pretty frequiently. This article will throw some light to those frequently occurring errors codes. The article will help you to identify and troubleshoot the actual issue.

Redirection 3xx

This class of status code indicates that further action needs to be taken by the user agent in order to fulfill the request. The action required MAY be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD. A client SHOULD detect infinite redirection loops, since such loops generate network traffic for each redirection.

301 Moved Permanently

The requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs. Clients with link editing capabilities ought to automatically re-link references to the Request-URI to one or more of the new references returned by the server, where possible. This response is cacheable unless indicated otherwise.

The new permanent URI SHOULD be given by the Location field in the response. Unless the request method was HEAD, the entity of the response SHOULD contain a short hypertext note with a hyperlink to the new URI(s).

If the 301 status code is received in response to a request other than GET or HEAD, the user agent MUST NOT automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which the request was issued.

Note: When automatically redirecting a POST request after
receiving a 301 status code, some existing HTTP/1.0 user agents
will erroneously change it into a GET request.

Client Error 4xx

The 4xx class of status code is intended for cases in which the client seems to have erred. Except when responding to a HEAD request, the server SHOULD include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents SHOULD display any included entity to the user.

If the client is sending data, a server implementation using TCP SHOULD be careful to ensure that the client acknowledges receipt of the packet(s) containing the response, before the server closes the input connection. If the client continues sending data to the server after the close, the server’s TCP stack will send a reset packet to the client, which may erase the client’s unacknowledged input buffers before they can be read and interpreted by the HTTP application.

400 Bad request:

This error happens because of the wrong syntax used by the client. Check and correct the given data and try again.

401 Unauthorized:

This error occurs due to failed authorization attempts. The reasons are supposed to be missing credentials or wrong credentials. The user may have tried to access the resource with no login data, missing login credentials or wrong login credentials. Recommended fix is to make sure that you are accessing the right resource and to check the username and password.

403 Forbidden:

A 403 error code refers that the user is trying to access restricted resources. The server understood the request, but is refusing to fulfill it. User may not have permission to access the files. The reasons may include permissions set to the resource using control panel. In case the access to the resource is must, revoke the permissions that restrict user access to the specified resource using control panel.

404 Not Found:

This error is shown when the requested resource is not found at the time of request. The reasons are the incorrect url provided to the application used to access the web. You may crosscheck the url to make sure that the specified resource is available.

Server Error 5xx

Response status codes beginning with the digit “5” indicate cases in which the server is aware that it has erred or is incapable of performing the request. Except when responding to a HEAD request, the server SHOULD include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. User agents SHOULD display any included entity to the user. These response codes are applicable to any request method.

500 Internal server error:

This error is shown when no specified error message is available. The error is due to faulty server side scripting or the wrong permissions/ownership set to the files. The solution is to correct the coding and to set the right permissions/ownership to the script files.

501 Not Implemented:

The server does not support the functionality required to fulfill the request. This is the appropriate response when the server does not recognize the request method and is not capable of supporting it for any resource.

If you still face a problem, please [contact the technical support]…