There’s a lengthy discussion in another thread where there are multiple solutions. I see you are a Plex Pass subscriber. You can try updating to the Beta version or downgrade to an older version to see if that solves your problem. Check your Plex Media Server > Updates folder to install older version. That worked for small selection of people. There are hardware factors that contribute to stuff like this. So there is no fix all solution until Plex releases one. You specify your PMS host is Windows 10. There was a recent patch. If changing PMS versions does not help you, you can try my solution. See this thread: SOLUTION: Conversion failed. The transcoder exited due to an error