Got "Printer error"
There are several reasons why print jobs get the status "Printer Error". However, it is always because your printer has canceled the print, and not because of the SimplyPrint platform. It’s either your printer or OctoPrint, that stops printing. The print is only stopped, showing "Printer Error" if it is such a critical error that the print cannot continue.
A sign that this has happened is that the printer has stopped out of the blue and has cooled down. These errors will often occur at the very beginning of a print while preparing the print
(typically by heating). Below are some of the reasons why your printer reports errors;
The printer is out of power
The most common reason for the printer getting this error is that the power to the printer's power supply is not turned on and therefore it cannot move the motors or heat up properly. Many printers look like they are on when the printer is "online" in SimplyPrint, but it might just be the Raspberry Pi that provides just enough power for the screen and in some cases also the fans to turn on.
You can test if the power is on by trying to move an axis and if nothing happens the power supply might be off. You could also see if the printer's screen turns off when you pull out the USB cable between the Raspberry Pi and printer connection cable.
Raspberry Pi and printer error
If the connection between the Raspberry Pi and the printer is lost in the middle of a print job, printing stops. This can happen if it is a bad connection cable or you have an old Raspberry Pi that can not handle the amount of data being transferred (seen in the Raspberry Pi "2" and "Zero" series).
It can also be due to too much electromagnetic interference. If the connection cable is not "shielded" (is poorly insulated) or your Raspberry Pi is not in a closed box then it can not be disturbed by other electronics like the printer itself.
Your printer's printhead is electrically split into two. There is a heating element and a temperature gauge which respectively heat up the print head and measure the temperature. It is necessary for the temperature gauge that it is properly connected to the print head, otherwise, it will not be able to measure the temperature correctly. When your printer prints, a large amount of vibrations can occur which can shake either the temperature gauge or the heating element loose over time. When the two parts are not thermally connected, the printer will not know how hot the heating element is and this triggers the thermal runaway protection which turns off the entire printer and ensures that the printer does not start a fire. If you find that your prints are stopped at the very beginning of the print while it is heating up, it may be a good idea to check if all the screws are tight and all the wires appear to be intact.
Minimum points not found
When your printer is homing, it expects all axes to hit their respective end contacts after a set number of rotations of each motor. If the contacts are not activated by then, the printer expects something to be wrong and it will restart itself. This can happen if the print head is prevented from moving due to any print residue on the build plate or a broken limit switch that does not trigger when it should. In this case, the axis would drive all the way to the switch but not stop the motor as usual. It will continue the attempt to home the axis and make a horrible noise. If this happens, the connection for the switch should be checked or the entire switch is replaced.