The Castle Doctrine Forums

You need to make sure the URL that you're adding tickets from (whatever the admin interface is loaded as in your browser address bar) matches the server URL in the settings.php file.

Some web hosts may automatically redirect you to the "www." version of the url.  If that's the case, make sure the "www." version appears in settings.php.

No need to muck around in the server.php file to fix this!  And really important to leave this check in place for security reasons.