Streaming app crash

Hello- 

I tried to use the streaming app with live tv- on an apple 4K tv.  It logged me in and then instantly logged be out and said it was not supported.

is this not supported on apple 4K???  The website says it is.  

I have called/chatted and NO one seems to be able to assist.  had to cancel service.  WHY????  

there is not an updated app- ONLY one to download.