Find an outlet that DOES work when the invertor is on. Plug in there. Sometimes the icemaker for the gas refrigerator will work. If not, just run a wire to the area and supply your AC power to the outlet that doesn't work now; you won't be using it any more.
The original plan was that you would use gas on the road and AC when in a park or using the generator. The old refrigerators used an enormous amount of electricity, so the refrigerator was disabled from working on the invertor. This was to save the batteries. The new household refrigerators use very much less current, and are fine for the purpose.
Tom & Jan ---- Westwing43
2005 NEWMAR KSDP 3910 NOW PULLING A 2014 CHEVY CAPTIVA