As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ABQ - FLIGHT 4182 - FLIGHT RETURNED TO FIELD AFTER RECEIVING A CABIN ALTITUDE CAUTION MESSAGE. THE CABIN PRESSURE ADJUSTMENT WAS INOPERABLE IN BOTH THE AUTO AND MANUAL MODES. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND THE AFT CARGO DOOR NOT PROPERLY SEATED. THE DOOR WAS CYCLED AND OPERATIONAL CHECKS PERFORMED. ALL CHECKS WERE NORMAL AND THE AIRCRAFT WAS RETURNED TO SERVICE.