It may help to take the ice maker plastic unit out of the refrigerator and rinse with warm water, then dry. There may be ice blocking the flap from closing. Also, check to see that the plastic unit is fully seated as it should be in the refrigerator itself.
Unplug it for a couple of minutes, Try again. It may have been hit with a surge. IF that is the case, you are looking at main control board and some money. Contact your homeowners insurance if a surge has damaged it.
This site shows the small tabs on the lense https://www.repairclinic.com/PartDetail/Large-Part-Image?imgID=1003776&locID=3336 A small screwdriver gently pull back in the opposite of the tab. Try with just fingers first as ofthe lense is too cold the tabs can snap off.