Sounds like you've lost 120v on one leg. I had that problem once a a CG. Plugged into their 50 amp receptical and only half of my trailer worked. I used my 30 to 50 adaptor and plugged into their 30 amp & everything worked. Turned out the CG had a bad breaker in their panel. As mentioned above, you may have a loose connection somewhere from your transfer switch to your main breaker.