<p>The BT Sport app closed on 12th October and has been replaced by discovery+. <a href="https://community.bt.com/t5/TNT-Sports-on-TV-Online-player/The-BT-Sport-app-is-closing-on-12th-October/td-p/2312034">Find out more about activating TNT Sports on the discovery+ app</a>.
That's your BT Sport subscription fixed - can you please confirm?
For your Chromecast issue, it's an odd one. The app on the phone is reporting that we soon as we tell the TV what to play, the TV ends the session. Unfortunately I don't log the reason that the TV has given for ending it, so I can't see why. I've added this logging to our next client update, due next week - if you still have your Android TVs next week then maybe we could pick this up again? 🙂