Verify that the fan for the radiator/evaporator is working, and that the evaporator is open to good airflow, rather then chocked with dead bugs and grass seed. Next evaluation of the radiator condition. If it is original replace it. If the car is seeing too high of engine coolant temperatures it will shut down the A/C. Engines are running in an over heated state for want of a radiator plunging up long before the drivers are made aware of a problem. And when your coolant falls on to the ground it’s kinda too late.