Can't use a custom https port

[phtmgt]

When mapping ports in Advanced, it says 'If you want to expose HTTP/HTTPS you should use the "Proxy" from the "Domains" tab.'

There's no Proxy in Domains.

Simple use case - I want to serve https over a custom port (e.g., 16750). Can't do it now. When I map 16750 to the app port from the advanced tab -> ports, I get no response, the browser just waits. Apparently, the request does not reach the respective app port. When I do the same over 80/443, it works (as the domain is added in the domains tab).