Rather than asking here, why not reach out to GAL Tech Support?.
https://www.gal.com/support/technical-support/They should be able to suggest likely causes and solutions. If I were to guess, the Parameter Units (PUs) you tried are not able to communicate with the Inverter (aka Drive) because there’s something damaged in the connector on the PCB or in the circuitry that transmits data between the PU and the Inverter CPU. That could be anything from mechanical damage to the connector pins to damage to an integrated circuit caused by a zap of static electricity.
