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. AIRCRAFT RETURNED TO FIELD WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT AIRCRAFT AND FOUND AFT CARGO DOOR NOT FULLY CLOSED. MAINTENANCE CLOSED DOOR AND PERFORMED OPERATIONAL CHECKS USING AIRCRAFT MANUALS. AIRCRAFT WAS RELEASED FOR SERVICE.