Octoprint stopped after 8 hours and the error displayed was:
State: Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2739
I noticed at around 22:00 2019-06-12
Then I have disconnected the raspberry and started a new print directly with SD card in the printer, used Octoprint only to monitor by the webcam
I found some alerts about power supply and temperature in the logs, I have no serial log
You have probably already solved this problem or moved on, but if not I have something to suggest. I was having a similar problem with the SerialException warning showing up unpredictably but inevitably. In my case it was preventing me from starting prints. In addition to the serial exceptions, I had irregular problems connecting to octoprint through octopi.local. When I was able to get to the logs, I had occasional warnings about under voltage. Looking on forums here is seems that the Pi is quite picky about power and main sign of power problems like these low grade brownouts are, frankly, all kinds of weird failures including dropping year printer. It seems that if odd things are going on, power supply should at the top of the list to check.
So I got a new power supply of known quality. And all the problems went away immediately. Since you know you have under-voltage issues, I would bet that is causing your problems. Get a power supply that does not produce ANY warnings. The one I got was a CannaKit 5V 2.5A. Cost just under US$10.
