Responded to no cooling call, thermostat was calling for ac. Indoor board was indicating that there was a call for cooling. The indoor fan and condenser were not running. Previous tech made sure all wires were tight, I double checked. All wires are good. Condenser board had an error code indicating low pressure lockout. Did a communication reset between indoor and outdoor units. System started up. Let system run for 35-40min pressure are good, temperature dropped over 5 degrees. Suspect system stopped working due to a power drop and needed to be reset.