amazon fire tv

Hello everybody, I wrote a simple proof of concept app using exoplayer to stream video from an external server. It works perfect when running on true Android tablet or Android smartphone. But when installed on an Amazon Fire TV this application launches correctly but at the time to play video...

I have a friend who's only Android device is an Amazon Fire TV. My app scales well to it. BUT he said his controller doesn't work well with it. Does anyone have advice on how I can make the app work better with his Fire TV controller? Thanks!