I had this problem suddenly occur in my refrigerator. Nothing seemed to have changed. Water pressure seemed ok given that the water dispenser had no noticeable change in flow. Temperature was maintained at 0 deg F in the freezer.
Solution: what ended up doing the trick was to remove the water filter, wipe off the connections and wipe the canister and reinsert the filter. Afterwards, something seemed to have gotten it back working. Ice started making again and the hopper is now full.