Tailscale client on iOS 15.6.1 can not connect to my camera server

Hi, i have an app to connect to my camera server, connection works when on WiFi
unfortunately i can not connect to the server using the servers tailscale ip address.

Trouble phone is a iPhone 6s with iOs 15.6.1 installed version 1.32.0 of tailscale app.

I have also a iPhone 11 with iOS 15.7 installed version 1.32.0 of tailscale app.

The iPhone 11 works correctly via tailscale, the iPhone 6s can not connect to the server.

On the iPhone 6s, deleted the camera server app and tailscale app and reinstalled them both, still the same result, no able to connect to the server.

Please hlep.