What you are describing points to you lost power to the camper. Either you tripped the main breaker inside the camper or out at the power post. Or the campground lost power.
The microwave and the AC unit are on different circuit breakers. AC on a 20 amp and microwave on a 15. I do not know your exact camper, but most are that way.
Also to note, your camper most likely is only setup on a 30 amp service. Running the AC unit uses a lot of power, at least 11 to 12 amps worth once it is past power up. If you attempt to run the microwave on hi for any length of time with the AC running with the compressor running, odds are high you will trip the breaker. This goes for running the HW heater on electric at 1,400 watts also.
These campers are not wired like a house that has good 200 amp service. Think of a camper as only able to power up one heat creating device at once. 1 hair dryer, 1 HW electric element, 1 toaster, 1 AC unit, 1 microwave and then you stay out of this issue.
The power convertor is using power all the time ~ 4 to 8 amps and more so if it is charging the battery. The fridge if you are running on 120 AC, is like having a 350 watt light bulb on using power. With those 2 units running, add a 3rd or 4th high power device and the breaker goes out. Especially if the CG has low voltage.
Hope this helps
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