As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF ROLL, DOOR WARNING LIGHT ILLUMINATED ON TAKEOFF. ABORTED TAKEOFF AND AIRCRAFT RETURNED TO BLOCK. INSPECTED CARGO DOOR AND FOUND SPRING ON CARGO DOOR DOWN LOCK DISCONNECTED. REATTACHED SPRING SYSTEM, OPS CHECKED GOOD PER MM CH 52.