I have a Longer LK5, based off the ender 3. It has a feature called recovery mode for if power goes out or other issues, you can resume the print. I jumped the filament sensor as well so it's always a solid signal. I've tried 3 different slicers, 2 different SD cards, and grounding to remove static electricity. The printer get about 2.5 hours into the print, then stops and goes into recovery mode. I can press resume and the head moves around tracing as it should, however the extrusion motor doesn't work. It retracts when at the end of a section, but doesn't push filament during the printing. I've tried different parts as well and all the same results. Please help. Thanks.