The brew unit filter is slightly blocked.
Clean the brew unit of the coffee machine once a week by hand.
Proceed as follows:
Disconnect the coffee machine from the power supply.
Open the appliance door on the right-hand side of the coffee machine.
Press and hold the button at the bottom of the handle of the brew unit (1).
While doing so, turn the handle to the left (2).
Carefully pull the brew unit out of the coffee machine.
Clean the brew unit by hand under warm running water without using any cleaning agent. The moving parts of the brew unit are lubricated. Cleaning agents will damage the brew unit.
Wipe any coffee grounds off the filters (see arrows).
Dry the funnel to prevent ground coffee from sticking to it the next time a coffee is made.
Drop a cleaning tablet into the top of the brew unit (arrow).
Push the brew unit with cleaning tablet back into the coffee machine, making sure it goes in straight.
Press and hold the button at the bottom of the handle of the brew unit (1).
While doing so, turn the handle to the right (2).
Close the appliance door.
Clean the brew unit with the cleaning tablet for degreasing using the Degrease brew unit or Clean brew unit maintenance program.