As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED CENTER CARGO DOOR AMBER CAUTION MESSAGE DURING INITIAL CLIMB. RETURNED TO FIELD DUE TO NOT BEING ABLE TO PRESSURIZE CABIN AND LANDED WITHOUT INCIDENT. MAINTENANCE PERFORMED OPS CHECK OF CENTER CARGO DOOR INDICATING SYS AND OPS CHECK OF CABIN PRESSURE. OPS CHECKED GOOD. NO DEFECTS NOTED. ACFT RETURNED TO SERVICE.