The relevance of frost free, is that the cold air is blown through ducts, usually in the back wall, which is where frost and ice form. Periodically, the machine is supposed to heat these ducts so if melts and drains out.
Quite a common problem is that if it builds up too much, for example if the door has been left open, door seals worn or the heater fails, the ducts become blocked, and air cannot circulate, and the temperature rises. The blockage continues to get worse and more solid.
Solution is to empty it, turn off, open both doors, for at least 24 hours or until water stops dripping inside the cabinet, and to the collection dish at the back, wipe it clean and dry, close doors and turn back on.
If you turn it back on before it has all melted out, you have wasted your time.
If it blocks again in less than a year, you have a fault, probably in the heater circuit. It may be uneconomical to repair.