Your engine block has a water leak.
The leak comes from a seal, or the filter pump or the heating resistance.
Please open the engine block and verify where the leak is coming from and that the joints are properly positioned and centered.
If the problem is not solved, the part that is involved has to be replaced (filter pump or heating resistance), according to the following procedure:
In case your product is out of warranty (more than 2 years), fill out the form (available here).
If your product is still under warranty (less than 2 years), fill out the form (available here), with your purchase invoice and a photo of the problem attached.