Printer(s) hang mid print

What is the problem?
Print stops mid print and hangs. Printer is at full temp, octoprint progress bar is stuck, octoprint says printing. This is not just one model that has this problem, on reprint the models work fine. sometimes all printers will hang at once.

What did you already try to solve it?
Turned on serial logging, looked for issues, was confused by what I saw.

As far as I can tell about line 54300 in this particular print something happened that the printer and the octoprint instance got out of sync in regards of which line in the file it was on/needed to send and kept getting further and further out of sync.

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)

My setup is 8 Prusa i3 Mk3 printers with the latest firmware. Groups of 4 are plugged into powered USB 3.1 hubs and connected to a raspberry pi 3b+. The Pi has been set up to run 4 instances of Octoprint at once and 98% of the time works flawlessly. OctoPrint : 1.3.9 can provide plugins used as well.

Serial.log and octoprint.log

So you're attempting to run not one but four printers from the same Raspberry Pi 3B+?

It's just my opinion of course but I wouldn't run more than one per Raspberry Pi.

And yet, this might be related to the random freezes related to the plus model of the Raspberry Pi 3B itself.

I also have this issue with the latest firmware update from Prusa (3.5.0) and OctoPrint 1.3.10rc4.
I'll check the serial log tomorrow after this current print.
For a short moment a saw the message "Full RX buffer" in the terminal.
For @Benjamin_Dalton runs 1.3.9, I assume it's a problem with the firmware.


After a time, some or more seconds, the print goes on.

That sounds like the printer board is indicating that OctoPrint has overrun the receive buffer.

Possibly adjusting the firmware could help in the RX section.