Plex DVR, Trying to watch Live TV but get error "Unable to tune channel (no parts)"

Please get the server logs so that the crashes can be investigated

First make sure the server has debug logging enabled
See
https://support.plex.tv/articles/201643703-reporting-issues-with-plex-media-server/

Then restart the server to get fresh logs created

Do whatever you did before to get the server to crash
Note down the time

Restart the server and download the server logs
and attach here with the details

See https://support.plex.tv/articles/200250417-plex-media-server-log-files/