DIAGNOSIS Yeah, this one's common. Water is escaping from the internal reservoir or tubing before it gets to the showerhead. The usual suspect is a cracked or disconnected silicone hose inside the unit.
FIX Unplug it, let it cool, and turn it upside down. Remove the base plate (usually held by small Phillips-head screws). Inspect the clear silicone tubing that runs from the water pump to the heating element and spray head. Look for cracks, loose connections, or pinholes. If you find a damaged hose, it needs to be replaced.
IF THAT DIDN'T WORK The leak could be from a seam in the internal aluminum water tank that has developed a hairline crack from thermal stress. That's a more serious internal repair.
HEADS UP Never move the machine while it's hot or full of water. Thermal stress and physical jostling are what cause these internal seals and tubes to fail.