As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW RETURNED TO FIELD WHEN AFTER TAKE-OFF THEY RECEIVED A CARGO DOOR WARNING LIGHT. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND THE CARGO DOOR HANDLE NOT FULLY SEATED. THE DOOR HANDLE WAS RESEATED, AN OPERATIONAL CHECK WAS PERFORMED,AND THE AIRCRAFT WAS PRESSURIZED. ALL CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE. NO PARTS WERE REPLACED.