2 possibilities
1. One of the circuit breakers on the inverter itself is tripped. There are buttons on the inverter itself to reset..
2. (and this was my case in my last coach)...not all outlets are going through the inverter. In that case, it is the way it is...when my inverter was on and I was not hooked up to power or generator, the bedroom outlets by the bed would not work and I had to run an ext cord for my CPAP machine. to the bathroom.
That last coach was Holiday Rambler and there were a few outlets not hooked up to the inverter.