As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DESCENDING OUT OF FL280 RECEIVED CABIN ALT CAUTION MESSAGE. COMPLIED WITH QRH. BOTH AUTO CONTROLLERS DID NOT WORK. MANUAL MODE BROUGHT CABIN UNDER CONTROL. THE MAINTENANCE CONTROL DAILY REPORT REFLECTS THE CREW DECLARED AN EMERGENCY.