Some of the oldest Roku TVs actually have a Roku stick connected inside a cover on the back of the TV. Those are usually the original MHL Stick, and it no longer supported. And you can't just connect a new Roku Stick in that port, as HDMI is different from MHL, even though they look the same.
And if your TV is one using the MHL Stick, it's going to start losing channel support in the near future. We could confirm what you have if you provide your TV's model info. Go to the Settings menu and look under System/About.
Dan
Roku Stick (3600), Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.
