I'm not sure why the microwave is flashing, but have you checked the breaker(s) on the generator itself, and in the RV's distribution panel? Even when they look OK, it's worth cycling them off & on to be sure they're not tripped. Also, some RV's require that you plug the shore power cable into an outlet powered by the generator.
Another issue can be that the GFI outlets(s) are tripped. Some outlets require a close look to see the GFI buttons.
Jim, "Mo' coffee!"
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')