As your fridge 120VAC outlet is technically 'outside' the trailer, it should
be on a GFCI. I would check those, and be sure that you have 120VAC power at the fridge outlet.
If all is good there, you might have a bad fuse at the control board of the fridge. You'll have to check your manual to see which one it is. They are under the black plastic cover that houses the control board.
Does it work on LP?