The filter combination in the wash cabinet is dirty.
Clean the filter combination as follows:
Turn off the dishwasher.
Turn the handle counterclockwise to release the filter combination (1).
Remove the filter combination (2).
Remove any coarse soiling.
Rinse the filter thoroughly under running water.
Use a soft cleaning brush to remove soiling.
To clean the insides of the filter, the flap must be opened:
Press the recessed grips together in the direction of the arrows (1).
Open the filter flap (2).
Rinse all the parts under running water.
Then close the flap so that the catch engages.
Reinstall the filter combination so that it lies flat in the base of the wash chamber.
Then turn the handle clockwise until both arrows point toward each other. This will lock the filter combination in place.