You could look at your 50 amp load center inside the RV and look to see what other circuit is NOT on the same leg as your converter. That circuit breaker would typically be in an opposed location as to the one that powers your converter.
IOW, if any or all of the other circuits in the RV operate, you could assume that your dogbone arrangement is correct and that a GFCI has been tripped.
Sometimes, an exterior GFCI or one that is well hidden is in front of the wall receptacles. It pays to look them all over. Also, some circuit breakers are hard to observe if in the tripped position. Turning them off and then to the on position is a good way of uncovering that situation.