open another service on different port

Hello, is there a way to call an internal application on other ports? I have this problem. I expose the web application via reverse proxy on port 80. I see the login and after entering, I need to be able to open a subdomain on a port other than 80 (1880). How can I do? Thanks

If you can’t configure an appropriate port on your server:

Then you’ll have to use something like a Portzilla subscription: