There are three possible reasons why this is happening. 1) Make sure the pan is properly seated in the machine. 2) The paddle will not rotate because it is stuck. 3) The belt is broken or is loose. Make sure the pan is seated correctly will solve problem one. Take the pan and paddle out of the machine and see if turns freely by hand. If no, then the sealed bearing is broken or something is causing the paddle to stick (put water in pan and soak it for awhile). If everything is ok keep the pan out of the machine and start a kneading cycle. Look through the lid to see if the motor shaft is turning. If no then the belt fell off or is loose. Hank