Interesting case - my home Ring system has many cameras with the main one of the front door bell. It works perfectly on my tablets and phones. It used to work perfectly every time on our new FamilyHub American fridge.
The current issue:
I want to see the front door and I get a message that "This feature is not supported". That messages appears for all the other camers as well.
I then restart the FamilyHub (Settings -> System -> Restart) and it work perefctly. I can see clear video from all my cameras.
I then go back to the fridge after an hour or so and it stops working again saying the same error message as above.
I then restart and everything works again for a moment.
Which proves that connection to Ring cameras works fine, Internet/WiFi is perfect, Ring API access is fine.
Samsung Ring App - well it seems like the only problem is that it ends the session too quickly. Samsung devs - could you have a look at session length params in your code?