went to Mirror my BT App to Apple Tv last night and message on TV says i cannot Mirror this app, try using the BT Sport App and Apple TV.
i am using both those apps listed. Why cant i mirror?
Have you taken a look at this thread Can I stream the BT Sport app to my TV?
As long as you aren't using the BT TV app instead of the BT Sport app then it should work fine.
Let me know how you get on.
Try it for me now please