Install tvos17.
just had a black screen but before I knew you could do this. I just unplugged everything at the back, waited 30 secs and plugged everything back again.
Because they are not tech savvy and have been lead to believe purchase from Android and/or the eco systems are separate. They don’t understand for example, Movies Anywhere, allows cross platform. Signal is another.
Seems reasonable, if no one is around to educate them, or assist them. Or that tv is on many tv’s now.