Melitta Caffeo Solo breaks off during pressing process

Hello all,

after I did the cleaning program of my Melitta Caffeo Solo last week, the machine breaks down during the pressing process, i.e. the coffee is ground, but during the pressing process the resistance becomes too great, so the machine stops the program and the ground coffee falls into the pulp container. If I fill the bean hopper with few beans so that no coffee is ground during 1/3 of the meal, the machine works, which could be an indication of too much ground coffee. However, due to the noise (the pressing process sounds very tortured) I suspect it is more likely mechanical resistance.
Does anyone know the problem and the cause of this phenomenon?

Thank you and best regardsTim