What usually caused this?
It means that the web server facing ‘internal‘ error before the output can be deliver to client. Basically something has gone wrong, but the server can not be more specific about the error condition. Since web server can be integrated with so many modules inside, this may cause by one of the module facing error when web server received the data from them.
Can you give me some example?
- An error in a CGI script that caused it to fail or output an error message before it started producing valid HTML. It usually happens if you have a syntax error in one of Perl/PHP CGI scripts.
- A permissions issue attempting to access a CGI script. Depending on how your web server is configured, quite often it’s not enough for the script to have “execute” permission, but it must also be owned by the correct user, and belong to the correct group.
- Invalid custom configuration files like .htaccess, web.config, version incompatibility or wrong syntax applied