Error-1 indicates that the laser distance sensor is faulty, please: 1. remove the cover on the laser distance sensor on the top of the machine, and start the machine to continue cleaning press and hold the OFF key to power the machine off, and then start the machine again to continue cleaning If the laser distance sensor does not rotate, use your finger or tool to toggle the laser distance sensor to check that no foreign matter gets stuck in the laser head, and then start the machine to continue cleaning.