My s23 ultra only has internal storage. I am downloading these videos to my device as downloaded content in plex. On some downloaded videos I get that error message and only playing with external player works. If I delete the offline video and play it with streaming normally there is no issue playing it normally through the plex player.
I have found some other people with the same issues but no solution. Android Playback (Download works, playback does not)
I am a lifetime plex subscriber and have been with plex since the beginning. This is the first time I’m having an issue