Hello Kluso67,
Thanks for reaching out to us for support. It's never fun when you're unable to play videos via the Apple TV app, and we are going to do everything we can to help you. When you have a free moment, please give the steps in the links below a try.
If you can't watch or stream movies and TV shows in the Apple TV app
Reset the Apple TV app
We ask you to give the above steps a try because they can potentially resolve your issue. If you're still experiencing the same problem after completing the steps above, please do not hesitate to reach back out to us with some specifics on what you're seeing so that we can continue troubleshooting with you.
We also noticed that you visited an article before posting, Get the Apple TV app on your smart TV, streaming device, or game console. Let us know if you have any additional questions we can assist with about that. If you do, please do not include any personal information in your reply.
Thanks for using the Apple Support Communities.
Cheers!