Hello Lorraine and welcome to the forum. Your breaker panel has two hot wire feeding it. L1 and L2. If both of your A/C are connected to L1 or to L2 this could be your problem. On my RV I have one A/C on L1 and the other A/C on L2 and I have no problem running both A/C's.
Also your problem may just be that both A/C's are just pulling to much current and will not run on 30 amps. Is there a way you can get your hands on a current meter and see just what kind of amps your A/C are pulling? Good luck and let us know what you find out.