Hotcat may produce '0 error' after changing from http to https with the following in the .htaccess file:
RewriteEngine On RewriteCond %{HTTPS} !=on RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
The error can be solved by adding this to LocalSettings.php:
$wgServer = '//example.com'; $wgCanonicalServer = 'https://example.com';