You may have already done this. But, 1) I would remove the app. 2) go to home>settings>system>power, and do the restart there. (If "fast start" is enabled, disable it before restarting). 3 Add the app again.
#2 is what I'm wondering if you did exactly that order, and that way.
Roku's problems are strange. Everyone seems to have a variation of the same problem. But, there's always something that isn't quite the same. You have to wonder if the tv manufacturers are using different hardware (new revision) during manufacturing. The Roku environment is like a mine field. There's a pattern, but it isn't exact. (I often wonder if they aren't in cahoots with the tv to manufacturer to send a signal to the tv to tell it to stop working after some period of time. Force you to buy a new tv.).
If the above doesn't work. I would do the factory reset. You wouldn't think it should work. But, stranger things have happened.
"People are often amazed at how much we’ve done with the number of engineers we’ve got." (Roku CEO Anthony Wood, Austin Statesman, Oct 4, 2019). "Amazed" is one way of putting it.
