You would have to leave the door open a few hours for all the frost to melt. It also has to melt behind the rear panel as well. If there was enough frost from the door being left open this could still be the cause of the problem. The defrost cycle will only run for so long. If there was too much frost from the door being left open, it may not have completely defrosted and not able to "catch up" I would leave the door open for a few hours and run a hair dryer into the lower vents in the rear of the freezer.
Be sure that it has completely defrosted. Then from there the machine will operator as normal. If however this happens again, then you need to have the defrost system checked.
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