Look for the raker bar at the top of the ice maker dispenser. It has plastic fingers that rotate and sweep ice through to the place it will be dispensed. Remove any crushed or cubed ice caught under the raker bar that prevents it from moving by carefully dislodging ice with an ice pick or screwdriver.
Unplug the ice maker if the raker bar still won't move. It's possible there are some ice cubes lodged in the internal parts of the ice maker that are keeping the fingers from raking ice all the way through to the collection bucket. Melting the ice by turning the ice maker off, or unplugging it, will remove the blockage. This technique can also solve a jam caused by ice blockage in the area where ice is dispensed.
Run your ice maker regularly to keep ice from getting lodged underneath the raker bar and to keep it from getting caught among the forks that push the ice through to the collection bin.