Diagnosis
The internal silicone tubing that carries water from the tank to the boiler has developed a pinhole leak or a connection has come loose. This is a less common but known issue.
How to Fix It
Unplug the machine and empty it. You'll need to remove the base plate (several small screws) to inspect. Look for the clear silicone tubing—check all connections at the water tank outlet and boiler inlet. A disconnected hose is an easy reconnect. A leaking hose needs replacement.
If That Didn't Work
The leak could be from the boiler seal itself. If you see water originating from the brass boiler cylinder, the seal/gasket has failed. This is a repair for a certified technician.
Heads Up
Do not operate the machine with a known leak. Water inside the base can short the electrical components, turning a simple hose fix into a much more expensive repair.