I call that "Plug into the generator powered outlet" a "Poor man's transfer switch" By the way, technically it is the BEST transfer switch, but the one time I needed to transfer in an RV park it was pouring down rain so I was kind of glad of my Automatic switch :).
If your RV is 50 amp (Plug has 3 flat blades one Round, U or D shaped) then check the generator circuit breakers and read on.
If it a 30 amp (2 flat, one not) then check the GFCI Sometimes the GFCI will trip when you plug into the generator
You can (And should) Plug in before you start the generator but turn OFF the breakers on the generator OR the main breaker on the service panel first. Then start the generator, wait 1/2 to 1 1/2 minutes and turn on the breaker(s)
Do not start the generator under load, the start up can, well trip the GFCI, it can also fry the converter, TV, Microwave, et-al.
Same with shut down, Kill the breaker(s) before killing the generator.
And one other thing.. Before you start it.. Install a Gen-Turi or equivlent please.