Outside of freezer is warm

The outside of my upright freezer is warm to the touch. And, I had a large ice buildup on the inside of the freezer. Freezer actually quit working while we were out of town for a weekend trip. Could it be a thermostat issue? Or, could the ice build-up be due to not allowing it to defrost have caused the unit to quit. And, what would explain the outside of the entire unit being warm to the touch?

Thanks for any ideas.

Follow-up. About 24 hours ago I turned the temp control from the max setting of 5 down to 2. The only thing I have in the freezer now is a cup of ice. It has remained frozen, which is good. Also, tonight, I felt around the entire outside casing, and it is the same temp as my garage, maybe even slightly cooler. Still thinking it is compressor related? I really do not know how to describe the frost pattern, just to simply say the metal shelves have a slight coating on them now.

Put thermometer in freezer near the back and tell us the temperature.

Just checked temp. The thermometer I have only drops down to 10F. It is sitting on 10F, with humidity just below 50%.

I put a different thermometer in the freezer tonight. It is indicating temp is between 4 and 7F. Also, humidity is in the 80% range. All of the coils inside the unit that carry the refrigerant have a coating of frost on them. No real pattern to the frost, just a coating on all of the lines. The temp control is set to "2" out of "5". Freezer has been running for 5 days solid now. Only thing in the freezer is a cup of water (of course, now it is solid ice). Also, the freezer unit does have a little movement back and forth, though as it is sitting my level indicates it is level both side to side and front to back.