The tank isn't seated correctly or the sensor is triggered.
- Remove the water tank and re-insert it firmly, ensuring it clicks into place.
- Check that the water level is between the MIN and MAX lines, not overfilled.
- Ensure the water softener filter (if installed) is properly seated and not blocking the tank from fitting fully.
If that didn't work: Unplug the machine. Remove the tank and check the interior of the machine's tank slot for any obstructions or visible damage. If the light persists with a correctly seated, properly filled tank, a sensor may be faulty. Contact De'Longhi Customer Service.