Find your inverter in the basement and check to see if ONE of the circuit breakers on it as tripped. These breakers are on the inverter itself and have nothing to do with your electrical panel.
Check to make sure that there are no GFI circuit outlets that have tripped. You probably have two in your coach.
If they are not tripped, check the voltage in and the voltage out of each side of your 50 amp breaker in your main panel.
If one side does not have voltage in, you MAY have a bad transfer switch or a bad plug on your power cord.
If one side does not have power out, you MAY have a bad 50 amp circuit breaker.