Similar issue here. Plex working on the Xbox One X app but on Android TV my JBL Link Bar videos stopped playing altogether - as in they don’t even load. In fact, I get the error “An error occurred while attempting to play this video. Please try restarting both the Plex Media Server and this app.”
I went into the settings, disabling/enabling things one at a time and re-testing. Turns out, disabling the new player did the trick. Once disabled, videos started playing again just fine.
