It's a 12v DC fridge. 50amp @120/240v AC is irrelevant.
What is the battery voltage? If the converter got shut off (or failed) and then you ran the battery down, it won't be happy.
You do have the battery disconnect switch in the "on" position, correct?
If the battery is good and the converter is charging, go check the fuse on the panel and the voltage across the fuse. If that doesn't show anything, I've heard rumor there is an inline fuse behind the fridge but ours hasn't had any issues, so never dug into it.