Dometic factory "control boards" had circuits embedded in plastic compound that is often prone to overheating. Symptoms are operation for up to a day or so, then hard cutoff.. Unplugging main power, and waiting a few hours will often enable board to start up again, but would shut off again, either on gas or 110V power. If that doesn't work, I'd join votes that either a 12V
fuse or 110V breaker has failed interrupting power to the refrigerator...
Several threads in this area with sources, and I'd definitely consider replacement board (Dragon??) at ~$110 before letting RV dealer or shop sell brand new Refrigerator (which is their preferred repair..).