The Roku Express in my Dad's bedroom has stopped playing after we go in & watch a specific TV show (NCIS). We then get a playback error message and have to restart the whole Roku device. (As in we are not able to navigate to any other show or app.) I've tried and this is the case if he tries to watch the show on either Paramount+ or Netflix.
Last night, he was able to watch a different show for an extended period of time, but this morning it was all playback errors this morning. It doesn't matter a hill of beans to me, but Dad likes Gibbs.
These things are just little special purpose computers. Like their big brothers sometimes clearing things out by restarting them is all they need.
Restart via Settings > System > System restart (for Roku TV: Settings > System > Power > System restart).
If a restart doesn't do it, try pulling the power plug to the device for a minute or so then plugging it back in.