As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT THE CREW DETERMINED THE EXTERNAL SERVICE PANEL ACCESS DOOR WAS OPEN. THE FLIGHT RETURNED TO CLT AND LANDED WITHOUT INCIDENT. MAINTENANCE CONFIRMED THE OPEN DOOR. INSPECTION OF THE DOOR AND FUSELAGE REVEALED NO DEFECTS. THE DOOR WAS PROPERLY SECURED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.