What are Error Codes?
These numbered error codes are how the Web server tells the userabout a status or error encountered.
There are many different errorcodes that a server can deliver, but these are a few of the more common codes.
401 – Unauthorized
Access to the URL resource requires user authentication which
1) has notyet been provided or
2) which has been provided but failed authorizationtests.
This is commonly known as "HTTP Basic Authentication". Unless youhave a good reason to do so, it is not recommended to redirect a 401 error.
403 – Forbidden
The request was a legal request, but the server is refusing to respondto it.
Unlike a 401 Unauthorized response, authenticating will make nodifference.
This is usually due to a scripting or permission(s) issue.
404 – Not Found
This response code indicates that the client was able to communicatewith the server but either the server could not find what was requested,or it was configured not to fulfill the request and not to reveal the reason.
Error 404 should not be confused with "server not found" orsimilar errors, in which a connection to the destination server cannot be made at all.
500 – Internal Server Error
Your Web server encountered an unexpected condition that prevented it from fulfilling the request by the client (e.g. your Web browser) for access to the requested URL.
This is a 'catch-all' error generated byyour Web server. Basically something has gone wrong, but the server cannot be more specific about the error condition in its response to the client.