Play to your tv not working

I have the “play to your tv” selected in iPad app. I also have channels turned on When I select a tv program On iPad I am given the option of watching it on iPad or Apple TV. If I select tv Nothing changes on Apple TV. It worked in the past. I hoped recent upgrade to tvOS 15 and TV and ios channels version 4.5.12 would solve the problem.

What else should I check.

Make sure you're not on guest WiFi on either device