DIAGNOSIS The noise is mechanical, caused by ice cubes jamming or sticking during the harvest (ejection) cycle. The ejector blades are hitting solid ice instead of freely twisting.
FIX Turn the unit off and unplug it. Remove all ice from the basket and the internal tray. Inspect the silicone ice tray. If ice is fused to it or there's visible scale, pour a 50/50 mix of white vinegar and warm water into the reservoir to just below the max line. Let it sit for 20 minutes, then run a full cleaning cycle by turning the machine on and letting it go through an ice-making cycle. Dump this first batch of vinegar-ice.
IF THAT DIDN'T WORK The grinding may be from the gear mechanism that turns the ejector blades. A small piece of broken ice or debris can get lodged in there. You'll need to carefully inspect and clear the area around the blades with a soft tool like a plastic spatula.
HEADS UP Never use a knife or metal tool to chip ice off the tray—you'll puncture the silicone coating and cause permanent sticking and noise.