As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PILOTS REPORTED THAT THEY COULD NOT START EITHER ENGINE USING EXTERNAL POWER BUT ENGINES STARTED FINE USING BATTERY POWER. MAIN POWER CABLES AND GROUND CABLE FOUND LOOSE AT GPU CONNECTOR. BOTH THE CONNECTOR STUDS AND THE POWER CABLE ENDS BURNED AND MELTED. PARTS REPLACED AS REQUIRED.