Geeetech

I spent a lot of time leveling and setting up the A20, and the print quality is a lot better now than at the beginning.
However, there is this one problem that drives me nuts:

Completely randomly in the middle of the printing process the printer will simply move the extruder up and back to the beginning, then beep. I turn the knob to choose "Resume Print", it wheels back and continues printing as if nothing happened. Then it stops again by itself and moves back "home". I press the "Resume Print" button again...rinse and repeat.

This can happen several times a minute, then not for like 10 minutes, then again more often. As I said, it's random. Normally the printer has this problem less when it just started, and more frequently later. It messes up my prints with blotches, and I'd really like to be able to leave the room for a few minutes and not stay with the printer all the time while it's in use, just in order to poke it to continue.

There's plenty of PLA material, and no obvious other reason for this behaviour, as far as I can see.
Do you guys have any idea?

I have the same problem with the A20 but only if I print from SD-Card. Randomly the printerhead moves to the left side and is waiting. After "resume print" the printjob continues. When I print via usb from Cura, then there is no problem. I have already tested another SD-Card without success.
So I have no idea, where the problem might be...

Thank you for replying, mike5723. I have never used the USB cable before, as I figured the SD card "must" be more reliable than that connection, but I'll give it a shot! (Note that I only ever used the SD card from Geeetech that came with the printer.)