As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER TAKEOFF THE LANDING GEAR WOULD NOT RETRACT AND THAT THEY RECEIVED A LANDING GEAR AIR/GROUND FAIL MESSAGE. THE CREW RETURNED TO FIELD AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND THE AIRCRAFT SAFE FOR FERRY FLIGHT AND THE AIRCRAFT WAS FERRIED TO KSDF. SDF MAINTENANCE REPLACED THE NOSE LANDING GEAR PROXIMITY SWITCH AND THE NOSE LANDING GEAR PROXIMITY SWITCH CONNECTOR. GEAR SWINGS AND OPERATIONAL CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.