As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2565 (PDX-ONT), AFTER TAKEOFF DURING CLIMB, RECEIVED A AFT CARGO DOOR WARNING MESSAGE. NO LOSS OF CABIN PRESSURE. CIRCLED FOR 30 MINUTES TO BURN OFF FUEL AND RETURNED TO PDX AND ACCOMPLISHED A UNEVENTFUL LANDING. MAINTENANCE ADJUSTED THE PX-102 PROX SENSOR IAW AMM 52-70-02-400-802-A02. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.