As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THE AIRCRAFT WOULD NOT PRESSURIZE AFTER DEPARTURE FROM CLT. AIRCRAFT RETURNED TO CLT AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND AFT CARGO DOOR NOT SECURED PROPERLY (DOOR INDICATION DEFERED). AFT CARGO DOOR HARNESS WAS REMOVED AND REPLACED CLEARING DEFERAL. TROUBLESHOOTING, REPAIRS, AND OPERATIONAL CHECKS WERE PERFORMED USING AIRCRAFT MAINTENANCE MANUALS. AIRCRAFT RELEASED FOR SERVICE.