DIAGNOSIS The thermal overload protector in the unit has likely tripped, cutting all power. This is a safety feature that activates if the compressor overheats, often from a lack of ventilation.
FIX Unplug the ice maker from the wall. Move it to a location with much better airflow on all sides, especially the back. Let it sit unplugged and cool down completely for at least 2 hours. This allows the internal thermal fuse to reset. Plug it directly into a wall outlet (not a power strip) and try the power button again.
IF THAT DIDN'T WORK The issue could be the low-voltage power adapter (the brick on the plug). Check the cord for any damage. Try a different, known-working outlet. If there's still no sign of life, the adapter or internal control board is probably faulty.
HEADS UP These units need serious breathing room. Stuffing it in a tight cabinet corner or against a wall will cause it to overheat and shut down every time. Give it space.