Doorbell 2 with FireTV Cube

I am using Doorbell 2 and a FireTV Cube. I always received a blue screen with the text someone is at the door on my tv screen when someone rings the bell and i can hear the ring through the tv. Since yesterday i only can hear the ring on the TV but the screen isn't showing anymore... is there anybody with a similar problem or does anybody know how i can reenable this feature?! I can't find it anywhere.... did a factory reset of my ring and the firetv cube already but still no screen.... the command "alexa show my door" works as normal and i can see the video....