Hello grangold,
The first thing we recommend is to restart the Apple TV following these steps found at Restart Apple TV - Apple Support. This can refresh the tvOS, apps and connections:
Restart Apple TV
Do any of the following:
• Press and hold both the Back
(Siri Remote 2nd generation or later) or
(Siri Remote 1st generation) and TV
buttons on the Siri Remote until the Apple TV status light blinks rapidly.
• Disconnect Apple TV from the power outlet, wait five seconds, then reconnect it.
• Open Settings
on Apple TV, go to System and select Restart.
If the issue continues, if you can provide the exact wording of any message received, others here may be able to offer suggestions.
Cheers.