As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, CREW RECEIVED A "SERVICE DOOR" WARNING LIGHT AND AUDIO SIGNAL. ACFT RETURNED AND LANDED WITHOUT INCIDENT. FOUND RT WING OTBD PRESSURE REFUELING ACCESS PANEL FWD FASTENER HAD RELEASED. FASTENER WAS SECURED AND ACFT DEPARTED.