So I’m not an expert, but I just spent an hour trying to troubleshoot this same problem for my mom over the phone and this was what finally worked. We enabled the auto adjust display refresh rate.
https://support.roku.com/article/115012823268
Now she can also watch the new Criminal Minds.
I am having the same problem, and no combination of display resolution or refresh rate solves it.
It started out as only affecting Paramount+, but now video shows in none of the channels. Netflix shows the title and rating on start, and Plex shows the player controls; but no video.
After six days of this nonsense, I am about ready to buy an AppleTV.
After disabling the AD Blocker on my router, my channels began to work without issue. Hope this works for you!
