As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SERVICE DOOR WARNING ILLUMINATED IN FLIGHT. DIVERTED AND ACCOMPLISHED A UNEVENTFUL LANDING. FOUND R-3 DOOR HANDLE NOT FLUSH, SUSPECT F/A ERROR IN CLOSING OF THE DOOR. PERFORMED VISUAL INSPECTION OF R-3 DOOR AND R-3 DOOR PROXIMITY SENSORS, REF AMM 31-62-00 AND AMM 52-41-00-710-801. NO FAULTS FOUND. ACFT OK FOR CONTINUE SERVICE.