DIAGNOSIS A leak from the base usually means an internal hose or connection has come loose, or the drain plug on the back isn't fully sealed. It could also be overflow from a clog.
FIX First, check the obvious: locate the silicone drain plug on the back lower corner. Make sure it's pressed in completely and seated flush. If that's fine, the issue is internal. You'll need to unplug, empty, and carefully tip the machine to look underneath. Often, the drain tube that runs from the ice basket area to the pump can pop off its connector.
IF THAT DIDN'T WORK The leak might be from the water inlet valve where the reservoir connects. Check the rubber gasket on the reservoir and the corresponding receiver inside the machine. If it's cracked or has debris, water will drip down inside the casing and out the bottom.
HEADS UP Don't run it until you fix the leak. Water inside the electronics is a quick way to kill the control board. If it's an internal hose, you can usually re-seat it without tools, but you have to be comfortable opening the base panel.