Not sure if this is a bug or intended. When the Redirect HTTP to HTTPS option is ticked the following lines for non-proxy subdomains are added to the domain.com.vhost file in the main server block: Code: if ($http_host = "sub.domain.com") { rewrite ^(?!/(sub|stats|error|\.well-known/acme-challenge))/(.*)$ /sub/$2 last; } However no lines are added for any subdomains setup as proxy, this can easily be fixed manually - I've simply added the following code to the server block for the reverse-proxy in question: Code: if ($scheme = http) { return 301 https://$server_name$request_uri; } Not a huge deal, the issue is whenever ISPConfig makes changes to the domain.com.vhost file the manual changes are lost.