Check if the door is entirely closed.
On the backside, open the detachable cooling filter.
Clean the filter under a running tap, and dry it well before reinstalling.
Make sure there is enough free space behind the machine. It should be at least 5 cm or 2”.
If new packages, that were not cooled, were recently placed, wait until the packages reach the correct temperature.
Reset the machine.
Open the door and push the ‘stand by’-button for 5 seconds, this will reset the machine. Then close the door.