DIAGNOSIS Water under the unit typically means an internal leak, often from a disconnected or cracked drain tube inside, or from the melting cycle not draining properly into the tray.
FIX 1) Unplug the machine immediately. 2) Pull out the drain tray and the water tank. 3) Carefully tip the machine onto its back (over a towel) to inspect the bottom. You'll see a small rubber drain tube. Make sure it's firmly plugged onto its nipple and hasn't popped off. If it's connected, check for cracks or splits along its length. 4) While it's tipped, use a towel to dry out the entire internal base pan. 5) Set it upright, plug it back in with the tank and tray still out, and run a clean cycle with just water. Watch carefully underneath to see if you can spot where the drip originates.
IF THAT DIDN'T WORK The leak might be coming from the water inlet valve on the back, where the tank connects. Check the silicone gasket on the bottom of the water tank for nicks or debris. Also, inspect the black rubber seal inside the machine's water port. A missing or deformed seal here will cause a drip every time the pump runs.
HEADS UP Continuing to run a leaking machine risks water damage to your floor and serious electrical damage to the appliance. Don't ignore a persistent leak. If you can't find and fix the source, it's time to call for service.