An unusually large amount of limescale has settled on the bottom of the water container.
Check the set water hardness level and set the level that applies to your fresh water.
You can determine the water hardness level for your water using the included test strip or by contacting your water authority or local authority. Water hardness is specified in water hardness levels (I to IV) or in German degrees of hardness (1 to > 21 °dH).
Descale the appliance as described in the operating instructions.