Phone app works but not always plugged into TV

The app works fine when playing on the phone. I have an HDMI adaptor to plug my phone into my TV so I can play videos there. The Hulu app works fine with the audio, but often pushes just a black screen with Hulu written on it to the TV though my phone has a banner saying "playing on TV". Sometimes the picture will show up & it defaults to closed caption, so I have to officially turn CC on to get turning it off to work.
Definitely needs some kind of bug worked out so the app will feed to the TV when the phone is connected to it.

winteroses about Hulu: Stream TV shows & movies, v4.10.1