Chest type freezer icing up real bad

Question

I have a chest type freezer that is not frost free. It is a 12 cubic ft. Problem is that it has been icing up real bad and I am having to clean it about once a month. The seal appears to be ok but that doesn't mean it is not bad. The unit freezes ok but it just keeps icing up. The majority of the ice is located at the front of the unit. When you open it up there is about 2 feet at the front of the unit that is icing.