The lint filter at the end of the hose which is connected to the rubber seal in the condensate container is blocked.
Clean the lint filter as follows:
Remove the condensate container.
Pull out the spout.
Guide the end of the hose through the opening and hold it securely with one hand.
Use your other hand to pull the lint filter off the hose.
Rinse the lint filter with a water jet until all the lint has been removed.
Place the cleaned lint filter back onto the hose.
Now feed the hose with its lint filter attached into the condensate container.
Reinstall the spout in the condensate container ensuring that it is positioned correctly.