Possible cause:
Water tank not filled to the MAX level during the course of the two rinse cycles.
Empty the drip tray, fill the tank up to the MAX level and run the third rinse cycle.
Run a rinse cycle according to the step-by-step guide:
It should have a minimum capacity of 2 litres.
Hot water is delivered from the coffee spouts.
Hot water is delivered from the cappuccino maker.
The steam light comes on.
Hot water is delivered from the coffee spouts.
Hot water is delivered from the cappuccino maker.
Hot water is delivered from the cappuccino maker.
The descaling is complete.