Rocket Chat android app doesn’t connect to rocket-chat server in non-standard port HTTPS


My RocketChat is behind the router. I configured port 6333 on the router so that it routes traffic to the Rocket Chat server.
(https://my-url:6333/) does work in any desktop browser and in the desktop app, but it doesn’t work in the android app.
Tested HTTP (http://my-url:6333/) , it works.