You may be in a campground where there is a significant load and a voltage drop causing the amperage to increase enough to open the A/C circuit breaker. If you have access to a volt meter, you should be reading at least 106 volts at any socket in the RV (preferably 112 - 120). If you're reading below about 103 volts, the campground "grid" is being overloaded and you're not getting adequate voltage.
I use one of these, plugged into a visible socket in the kitchen. If it's not "in the green" I start powering down my trailer.
Plugging into a "low voltage" power source is one of the most common problems in older (or very busy) campgrounds and is a very good reason to consider a voltage power protector/surge guard.