Hi there, sampo139!
Thanks for reaching out to the Apple Support Communities! It sounds like you're having an issue with the Apple TV app not working properly on your Smart TV. I suggest checking out this article to Set up the Apple TV app on your smart TV or streaming device and follow the steps here:
You can restore the Apple TV app to its original settings, remove all of your personal information, and sign out of all accounts. Just go to Settings > Reset.
To use the Apple TV app, you'll need to set it up again."
If you still have an issue after resetting the app, I would recommend reaching out to Apple directly by checking out this link to Contact Support and they will be more than happy to proceed with additional steps.
Have a great day!