This may not be of much help, as this is just a fix to keep it running after crash. Use restart on crash to automatically bring back the server on crash. Mine is doing the same when I’m asleep.
It’s a separate software that comes up right away in Google.
The bonus of the software is you can enable logging too to see when Plex crashed to the second. Since my post the other day it has restored Plex 3 times now. It’s saving my sanity