I have exactly the same problem on Four Samsung TV’s, three new only 2 months old and 1 four years old.
What I have found is that you must EXIT the app cleanly and not simply swap to another app (e.g. Netflix) or turn off your TV.
I find the app works fine every time if you click the back button till you get a “EXIT” prompt, otherwise like others I have to reinstall to get it working again…!!!
To me this is not ideal on four TV’s with non techie’s around me, visitors and kids…
Plex Please fix e.g. some sort of auto exit after x hours to resolve this issue