HTTP Error Codes - 401 Access Denied , 403 Forbidden , 404 Not Found , 500 Internal Server Error

HTTP Error Code and their definition

100 - Continue.
101 - Switching protocols.
200 - OK. The client request has succeeded.
201 - Created.
202 - Accepted.
203 - Non-authoritative information.
204 - No content.
205 - Reset content.
206 - Partial content.
207 - Multi-Status (WebDay).
301 - Moved Permanently
302 - Object moved.
304 - Not modified.
307 - Temporary redirect.
400 - Bad request.
401 - Access denied.
401.1 - Logon failed.
401.2 - Logon failed due to server configuration.
401.3 - Unauthorized due to ACL on resource.
401.4 - Authorization failed by filter.
401.5 - Authorization failed by ISAPI/CGI application.
401.7 – Access denied by URL authorization policy on the Web server.
403 - Forbidden. 
403.1 - Execute access forbidden.
403.2 - Read access forbidden.
403.3 - Write access forbidden.
403.4 - SSL required.
403.5 - SSL 128 required.
403.6 - IP address rejected.
403.7 - Client certificate required.
403.8 - Site access denied.
403.9 - Too many users.
403.10 - Invalid configuration.
403.11 - Password change.
403.12 - Mapper denied access.
403.13 - Client certificate revoked.
403.14 - Directory listing denied.
403.15 - Client Access Licenses exceeded.
403.16 - Client certificate is untrusted or invalid.
403.17 - Client certificate has expired or is not yet valid.
403.18 - Cannot execute requested URL in the current application pool. This error code is specific to IIS 6.0.
403.19 - Cannot execute CGIs for the client in this application pool. This error code is specific to
403.20 - Passport logon failed. This error code is specific to IIS 6.0.
404 - Not found.

404.0 - (None) – File or directory not found.
404.1 - Web site not accessible on the requested port.
404.2 - Web service extension lockdown policy prevents this request.
404.3 - MIME map policy prevents this request.
405 - HTTP verb used to access this page is not allowed (method not allowed.)
406 - Client browser does not accept the MIME type of the requested page.
407 - Proxy authentication required.
412 - Precondition failed.
413 – Request entity too large.
414 - Request-URI too long.
415 – Unsupported media type.
416 – Requested range not satisfiable.
417 – Execution failed.
423 – Locked error. 
500 - Internal server error.
500.12 - Application is busy restarting on the Web server.
500.13 - Web server is too busy.
500.15 - Direct requests for Global.asa are not allowed.
500.16 – UNC authorization credentials incorrect. This error code is specific to IIS 6.0.
500.18 – URL authorization store cannot be opened. This error code is specific to IIS 6.0.
500.19 - Data for this file is configured improperly in the metabase.
500.100 - Internal ASP error.
501 - Header values specify a configuration that is not implemented.
502 - Web server received an invalid response while acting as a gateway or proxy.
502.1 - CGI application timeout.
502.2 - Error in CGI application.
503 - Service unavailable. This error code is specific to IIS 6.0.
504 - Gateway timeout.
505 - HTTP version not supported.