Amazon Prime not syncing with Up Next in TV App

Hi there,

a few days ago my Prime app stopped syncing with the TV app. Things I start watching on Prime don't go into the Up Next queue. TV shows and films that already were in the queue and which I watch further don't sync the progress with the TV app. I'm in Germany and the only other app I have connected to the TV app works without a problem.

I already tried force quitting both the Prime and the TV app, restarting the Apple TV 4 from system settings, and resetting the Apple TV 4. All without success. Is this a Prime problem then or is there anyone else who's having the same issue?