I have this issue occasionally when plex thinks its recording live-tv when its not. The circle indicator never increases past a certain port. Eventually I get an error “could not move recorded media to destination” in the PVR Schedule list. Can happen anywhere from once every 3-4 days to twice a day.
For the forum to be able to help typically you will need to post what version of PMS you are using, and also debug level Plex logs from shortly after a failure.
If you haven’t, you may want to review this thread which is the main thread regarding the error you posted.