Turn everything off and unplug from your AC shore power source. Find the transfer switch box and take the cover off (there may be two box that look the same). Check to make sure all wires are connected tightly and make sure none have come out of place.
Next, leave the cover off the box (if you are not confident, do not do this next step), turn the AC shore source on and check the incoming line for power. If none, try it with the generator on. If none from the generator check the circuit breaker on the top of the generator itself. Also, check the circuit breakers on the inverter.
Good luck,