DIAGNOSIS Something is physically obstructing the Lidar turret, preventing it from seating properly in its 'home' position. Usually, it's a hair or string wrapped around the spindle underneath the rotating cover.
FIX Gently press down on the plastic cover of the spinning Lidar tower and rotate it by hand. Look around the base of the spinning part, where it meets the stationary body. Use tweezers or your fingers to remove any hair, thread, or debris wrapped around the central spindle. Rotate it a full circle to check the entire circumference.
IF THAT DIDN'T WORK The Lidar module's motor or sensor might have failed. Try a hard reset: hold down the power button on the robot for about 15 seconds until it completely powers off. Wait a minute, then turn it back on.
HEADS UP Never store the robot under a low table or couch where the Lidar can hit something. That constant forced stoppage can lead to this error or damage the motor.