If you are running MediaWiki on a shared hosting service or behind a proxy server and you are experiencing issues with internal server host names or redirection, there are a few steps you can try to fix the problem:
Check the value of the $wgServer setting in your LocalSettings.php file. This setting specifies the protocol and server name that should be used when generating URLs for your MediaWiki installation. Make sure that it is set to the correct value for your server.
Check the value of the $wgUsePathInfo setting in your LocalSettings.php file. This setting controls whether MediaWiki uses "pretty" URLs or not. If it is set to true, MediaWiki will use "pretty" URLs, which may cause issues with redirection on a shared hosting service or behind a proxy. You can try setting it to false to see if this resolves the issue.
Check the RewriteRule directives in your .htaccess file. If you are using Apache as your web server, the RewriteRule directives in your .htaccess file may be causing issues with internal server host names or redirection. Make sure that the RewriteRule directives are correctly configured for your server.
Check the configuration of your proxy server. If you are running MediaWiki behind a proxy server, the proxy server may be causing issues with internal server host names or redirection. Make sure that the proxy server is correctly configured to pass traffic to your MediaWiki installation.
Check the logs for your web server and proxy server. If you are still experiencing issues with internal server host names or redirection, you may want to check the logs for your web server and proxy server for additional clues about the problem. The logs may contain error messages or other information that can help you troubleshoot the issue.
If you are still having trouble after trying these steps, you may want to seek assistance from your hosting provider or from the MediaWiki community. There are many experienced MediaWiki users who may be able to help you troubleshoot the issue.