Check the circuit breakers on the generator itself since this is a common cause of this problem. Last time we had it when they did some welding on our RV.

we had a Motorhome once that did not have an "automatic changover" feature for the generator. We had to plug the electric cord (that normaly goes to the campground pedistal) into a receptical (that was inside the same compartment as the cord) to run off the generator.

Phil