Liebherr ICBN 3366 - No Frost is no longer working. Who knows this problem?

Hello

We have a refrigerator-freezer combination from Liebherr (ICBN 3366-20) and it has No Frost. After forgetting to properly close the freezer door once about a year ago (one compartment was stuck...), the No Frost no longer works. When defrosting manually, a light layer of ice forms on the baskets within one day again, and over time icicles and similar form.
The fridge is now almost 3 years old, the ice cube maker works as it always did before. Otherwise everything runs fine, only No Frost is either broken or disabled. Does anyone have any advice?

I am not sure how NoFrost works, but could it be due to a clogged condensate drain?

According to the manual, the moisture in the freezer compartment should condense on the evaporator and is periodically defrosted and evaporates. For some reason, however, the machine does not do this. Everything in the refrigerator is still running and the condensate drain is clean and empty.

Liebherr contacts ?

Liebherr does not need to provide support. You are then referred to the local electrical stores. I have already called the kitchen studio, but they could not help me there.

Crazy with prices like that