DIAGNOSIS Water pooling under the unit almost always means a cracked or dislodged internal water tube. The most common failure point is the silicone inlet tube that connects the water reservoir to the thermoblock pump. It gets brittle with heat cycles and cracks.
FIX You'll need to disassemble the unit. After unplugging, remove the outer shell. You'll see a network of clear or white silicone tubing. Run a dry cycle with the shell off (be careful) and look for the drip. The culprit is often the short 90-degree elbow connector. These tubes are press-fit onto plastic barbs. Replace any cracked tubing with food-grade silicone tubing of the same inner diameter.
IF THAT DIDN'T WORK If the tubes look fine, the leak could be from the thermoblock itself. Hairline cracks can develop in the aluminum casting. You might see mineral scale around a crack. A leaking thermoblock is not repairable; the whole heating unit must be replaced.
HEADS UP Don't just keep using it leaking. Water getting into the electronics base will eventually short out the control board, turning a tube fix into a complete machine loss.