As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MSO - FLIGHT 2349 - AIRCRAFT WOULD NOT PRESSURIZE AFTER TAKEOFF IN MANUAL OR AUTO MODES. RETURNED TO THE FIELD AND ACCOMPLISHED A UNEVENTFUL LANDING. MAINTENANCE REPLACED THE AFT CARGO DOOR SEAL. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.