Plate is Jammed
The shredding plate might be jammed or worn out. Most disposers have an opening at the bottom of the housing. If the shredding plate is stuck, insert either a disposer wrench or a ¼ inch Allen wrench into the bottom of the disposer and wiggle the shredding plate back and forth until it moves freely. If the disposer does not have an opening at the bottom, insert a broom handle into the drain opening and try to wiggle the plate.