We had our 2nd trip in our new to us 03 Holiday Rambler Scepter- plugged in to shore power the management system flashed then stuck on 50-amp even though the shore power was 30. Even though it read 50-amps it was not recognizing shore power., the inverter panel was reading waiting for AC power. Nothing would work. We tried the GFCI hidden on the side of the bedroom draws, there was also one in the engine compartment nothing helped. Found out the 50-30 plug was bad, Bought a new one , still nothing. Read the owners manual, there is a safety feature that shuts everything down if there is an overload or unstable power. With ours you had to start the generator , we ran it for about 1/2 hour everything was working on the generator power. When we shut off the generator it transferred to shore power and everything worked. I guess it's a way of resetting the system . Good luck hope this helps!
Dave