Interpretation of common HTTP error codes

HTTP Common Errors

HTTP Error
400 Request Error
The server was unable to understand the request because of a malformed syntax. Without modification, the client program cannot repeat the request.

HTTP Error 401
401.1 Unauthorized: Login failed
This error indicates that the certificate that is transmitted to the server does not match the certificate that is required to log on to the server.
Contact the administrator of the WEB server to confirm that you have permission to access the requested resource.
401.2 Unauthorized: The server's configuration causes logon failure
This error indicates that the certificate that is transmitted to the server does not match the certificate that is required to log on to the server. This error is usually caused by not sending the correct WWW validation header field.
Contact the administrator of the WEB server to confirm that you have permission to access the requested resource.
401.3 Unauthorized: Not authorized due to ACL in resource
This error indicates that the certificate transferred by the customer does not have access to a specific resource on the server. This resource may be a Web page or file that is listed in the address line in the client computer, or it may be another file on the server that is required to process the files that are listed in the address line in the client computer.
Log the full address you are trying to access and contact the administrator of the WEB server to verify that you have access to the requested resource.
401.4 Unauthorized: The authorization service is rejected by the filtering program
This error indicates that the WEB server has a filter installed to verify the users who are connected to the server. This filter denies access to the certificate of Authenticity that is connected to this server.
Log the full address you are trying to access and contact the administrator of the WEB server to verify that you have access to the requested resource.
401.5 Unauthorized: Authorization failure for ISAPI/CGI application
This error indicates that the address in the Web server you are trying to use has an ISAPI or CGI program installed and is used to authenticate the user's certificate before continuing. This program denies access to the certificate of Authenticity used to connect to the server.
Please log the full address you are trying to access and contact the administrator of the Web server to confirm that you have access to the requested resource

HTTP Error 403
403.1 Forbidden: Prohibit execution of access
This error can be caused if a CGI, ISAPI, or other execution program is executed from a directory that does not allow execution of the program.
If the problem persists, contact the administrator of your WEB server.
403.2 Forbidden: Disable Read access
This error can be caused if there is no default Web page available or directory browsing is not enabled for this directory, or if an attempt is made to display an HTML page that resides in a directory that is marked only for Execute or script permissions.
If the problem persists, contact the administrator of your WEB server.
403.3 Forbidden: Prohibit Write access
This problem can be caused if you attempt to upload or modify a file in a directory that does not allow write access.
If the problem persists, contact the administrator of your Web server.
403.4 Forbidden: Require SSL
This error indicates that the Web page you are trying to access is protected by Secure Sockets Layer (SSL). To view, you must enter https://in front of the address you are trying to access to enable SSL.
If the problem persists, contact the administrator of your Web server.
403.5 Forbidden: Requires SSL
This error message indicates that the resource you are trying to access is protected by 128-bit Secure Sockets Layer (SSL). To view this resource, you need a browser that supports this layer of SSL.
Verify that your browser supports 128-bit SSL security. If supported, contact the administrator of the Web server and report the problem.
403.6 Forbidden: Deny IP address
This problem can be caused if the server contains a list of IP addresses that are not allowed to access this site, and the IP address that you are using is in this list.
If the problem persists, contact the administrator of your Web server.
403.7 Forbidden: User certificate required
This issue is caused when you try to access a resource that requires the browser to have a user Secure Sockets Layer (SSL) certificate that is recognized by the server. can be used to verify whether you are a legitimate user for this resource.
Contact the administrator of your Web server to obtain a valid user certificate.
403.8 Forbidden: Prohibit site access
This problem can occur if the Web server is not servicing the request, or if you do not have permission to connect to this site.
Please contact the administrator of the WEB server.
403.9 Forbidden: Too many users are connected
This problem can occur if the Web is too busy and cannot process your request because of excessive traffic. Please connect again later.
If the problem persists, contact the administrator of your WEB server.
403.10 No access: Invalid configuration
There is a problem with the configuration of the Web server.
If the problem persists, contact the administrator of your Web server.
403.11 Forbidden: Password changed
This error is caused by the user entering the wrong password during the authentication process. Please refresh the page and try again.
If the problem persists, contact the administrator of your Web server.
403.12 Forbidden: Mapper denied access
Deny user certificate attempts to access this WEB site.
Contact your site administrator to establish user certificate permissions. If necessary, you can also change the user certificate and try again.

HTTP Error 404
404 Not Found
The WEB server could not find the file or script you requested. Please check the URL to make sure the path is correct.
If the problem persists, contact your server's administrator.

HTTP Error 405
405 This method is not allowed
The method specified in the request line is not allowed for the resource identified by the request. Make sure that the correct MIME type is set for the requested resource.
If the problem persists, contact your server's administrator.

HTTP Error 406
406 Not acceptable
Depending on the "accept" heading that is sent in this request, the resource identified by this request can only produce a response entity with a content feature that is "not acceptable".
If the problem persists, contact your server's administrator.

HTTP Error 407
407 Proxy Authentication Required 
You must verify this proxy server before you can provide services for this request. Please log on to the proxy server and try again.
If the problem persists, contact the administrator of your WEB server.

HTTP Error 412
412 Prerequisites Failed 
When a precondition is tested on the server, the prerequisites given in the partial request header field are estimated to be false. The client places the prerequisites in the current resource Metainformation (header field data) to prevent the requested method from being misused to other resources.
If the problem persists, contact the administrator of your WEB server.

HTTP Error 414
414 Request-uri too long 
The Request-url is too long and the server refuses to service this request. This condition can occur only under the following conditions:
The client incorrectly translates the POST request to a GET request with longer query information.
The client encountered a redirection problem (for example, a redirection prefix that points to its own suffix).
The server is suffering from customer interference that attempts to exploit security vulnerabilities in certain servers that use fixed-length buffers for reading or executing request-uri.
If the problem persists, contact the administrator of your WEB server.

HTTP Error
500 Internal error of the server 
The WEB server cannot perform this request. Please retry this request later.
If the problem persists, contact the administrator of your Web server.

HTTP Error 501
501 Not implemented 
The WEB server does not support the functionality required to implement this request. Please check the URL for errors and if the problem persists, contact the administrator of the Web server.

HTTP Error 502
502 Gateway Error 
When used as a gateway or proxy, the server receives an invalid response from the upstream server that is accessed when it tries to implement this request.

Interpretation of common HTTP error codes