As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INFLIGHT MAIN CARGO DOOR INDICATION ILLUMINATED DURING CLIMB OUT OF CVG. FLIGHT CREW ELECTED TO RETURN TO CVG. AIRCRAFT LANDED WITH OUT FURTHER INCIDENT. AIRCRAFT WAS GROUNDED BY MAINTENANCE. MAINTENANCE PLACED ON D.I. IAW MEL 52-71-1-2 MBCB 8-14-23 PLACARD INSTALLED C/W MX PROCEDURES TO VERIFY DOOR IS LATCHED AND LOCKED. AIRCRAFT RETURNED TO SERVICE.