I would get an outlet tester:
https://smile.amazon.com/Sperry-Inst...NsaWNrPXRydWU=
They come in handy on an RV. I would not think the problem is the generator.
Last year when I plugged into the 50 amp plug on the RV pedestal I wired, it did not work. Then it did. This year the 50 amd plug did not work but the 30 amp did.
Outlet tester said there was a problem.
Had to replace the 50 amp breaker on the pole. Then everything was good in the MH. However, the outlet tester said there was a problem in the 30 amp camping trailer. Turns out BIL had replaced the plug and not wired it correctly.
You problem could lots of things.