What are Error Codes?

These numbered error codes are how the server tells website visitors about an error encountered. There are many different error codes 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 either has not yet been provided, or which has been provided but failed. This is commonly known as password protection. Unless you have 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 respond to it. Unlike a 401 Unauthorized response, authenticating will make no difference. This is usually due to a scripting or file permissions issue.

404 : Not Found
This response code indicates that the visitor was able to communicate with the server, but either the server could not find what was requested, or it was configured not to fulfill the request and not reveal the reason. Error 404 should not be confused with "server not found" or similar 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 visitor. Basically, something has gone wrong, but the server can not be more specific about the error condition in its response to the visitor.

Common problems

If you are still seeing the HostGator error pages, try refreshing your browser (ctrl + F5). If you still see the HostGator pages, please add this code to your .htaccess file in the public_html directory.
ErrorDocument 403 /403.shtml
ErrorDocument 404 /404.shtml
ErrorDocument 500 /500.shtml

You can even use existing pages as the resulting page. Say you don't want any visitors seeing 404 errors on your site. You can make your home page the result, like so:
ErrorDocument 404 /index.html

If Internet Explorer is not displaying the custom error page, it is likely because the error page must be larger than 1 kilobyte.

There are many error pages which may be defined.
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
How can I revert back to the default error pages?
Simply delete the error page from the public_html folder:
404.shtml
403.shtml
500.shtml

Successful Client Requests:
200 OK
201 Created
202 Accepted
203 Non-Authorative Information
204 No Content
205 Reset Content
206 Partial Content

Client Request Redirected:
300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
303 See Other
304 Not Modified
305 Use Proxy

Client Request Errors:
400 Bad Request
401 Authorization Required
402 Payment Required (not used yet)
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