The coffee machine is not producing milk foam.

Reason: The automatic milk frothing system is dirty or not properly assembled.

Solution: Clean the automatic milk frothing system and ensure its correct assembly.

Reason: The hole of the milk tube connector is blocked by milk residue.

Solution: Refer to "Daily Cleaning Products" and follow the steps of "Cleaning Bottle and Tube" to clean and ensure that the holes on the tube are clean. You can use a needle or cleaning brush to clean the holes.