I can see several crash reports from your server May 29th and then on June 12th to June 16th. All the crashes are in the intel hardware encoding dllL mfx_mft_h264ve_32.dll
These are known to arise if the Plex Media Server is run as a service, scheduled task or through RDP,
The solution is a choice between
hardware acceleration being disabled,or
not to run Plex Media server as service / shceduled task or via rdp
Hardware Acceleration setting is in server / settings / transcoder