That is what this crash is associated with - it is because there is no desktop session
As from version 1.18.4.2164 of Plex Media Server, there is a new Advanced Setting for the Transcoder that allows users to disable Hardware Encoding whilst leaving Hardware Acceleration enabled and used for decoding. This hopefully would avoid the crashes and would be a better option than disabling all hardware acceleration
See Plex Media Server - #308 by ahiyahiya
- (Preferences) Enable “Use hardware-accelerated video encoding” by default.