2008 discovery 40x. At some campgrounds when on shore power, our whole electrical system shuts down, (no power). Go on generator and power comes back. We "re-set" the inverter and go back on shore ...
I would check the output of the transfer switch when on shore power and everything is dead. If you don't have power than you probably have a bad shore power relay in the transfer switch. If you do have power there than probably a loose connection or the inverter.