@BKK20
Exactly. The port is always added as it is an integral part of the URI, but when omitted in the URI, this is auto-completed with :80 and :443 respectively for HTTP and HTTPS, as we already told you twice. AirVPN does not allow remote inbound port forwarding of ports between 1 and 2048, as reported in the FAQ and the manual. AirVPN is not a hosting provider.
You might rent a VPS or a dedicated server to run your web server or any other service, and then you may make your service reachable on any port you like. If you don't need any privacy or anonymity layer for your web server (or other service), that's a logical solution, and it's not expensive.
Kind regards