I am having the exact same problem.
I have an ipad, and on it I can access the Watch TCM app, watch movies, etc... ( and I am logged in with Watch TCM/cable provider). When I connect to the HDMI to my TV I can view on the TV screen the app, scroll through the various menus but when i want to watch a movie all I get is the audio of the movie coming through my TV speakers. I thought maybe this was some sort of restriction placed by TCM and my Cable provider. I dont like it. I'm in my home, I pay an arm and a leg for my cable subscription and I want to watch TCM movies on my own schedule. I thought this would be easy. What was I thinking...