Apple TV app stopped working on our Roku

We have Apple TV+ for free through T-Mobile. It worked fine until recently. Now the series we tried to watch won’t load. Instead an error popped up stating that the video is not available.I signed out hoping that that would fix everything, but now the app won’t let me sign in anymore. Instead it keeps showing a small spinning wheel, as if it’s loading. I am able to watch Apple TV+ on my iPad though, so I think it must be a Roku issue. I already removed the Apple TV app on our Roku, and I also tried to reset the settings of the Apple TV app. Still it won’t let me sign back in on the Roku app. How can I fix it please?