As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT 12000FT 10 MILES NORTH OF IAD, CREW RECEIVED FWD CARGO DOOR WARNING MESSAGE. CREW RAN CHECKLIST AND RETURNED TO IAD. AT THE GATE 9L MX FOUND FWD CARGO DOOR LATCH WAS NOT SECURED PROPERLY. RE-SECURED THE LATCH, OPS CHECKED GOOD REF AMM 52-30-00.