It could be your transfer switch. I have seen where the relay sticks in the transfer switch and doesn't switch on to allow power to the coach.
See if you can find your transfer switch. Make sure the generator is off (and shore power is unplugged). Take the cover off the transfer switch and you will see the relay. Try tapping it a couple times and then try the generator again.
If you can find some electrical contact spray or silicone spray, you can try spraying the relay with it.
Let us know.....
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