See:
How to use the Apple TV channel on your Roku® streaming device
https://support.roku.com/article/360036652634
and the links on this page Get the Apple TV app or Apple TV+ app on your smart TV, streaming device, or game console - Apple Support --> https://support.apple.comHT209440
Sometimes it helps to have the devices involved take a fresh look at settings:
- Try signing out of accounts and back in again.
- Restarting is a simple step that can resolve many unexpected behaviors.
If a problem persists, particularly over several days, try contacting Apple for assistance:
Click here --> Choose your country or region - Official Apple Support Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.
or:
"See a list of Apple phone numbers around the world."
Click here --> Contact Apple for support and service - Apple Support