As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) UPON REACHING CRUISING ALTITUDE, THE AIRCRAFT STARTED LOSING PRESSURIZATION. THE CREW DONNED THEIR OXYGEN MASKS, AT WHICH TIME THERE WAS A TOTAL LOSS OF PRESSURIZATION. UPON RETURNING TO MAINTENANCE, FOUND THAT THE SLEEVE CONNECTING THE DUCT TO THE WATER SEPARATOR HAD BECOME DISCONNECTED EVEN THOUGH THE CLAMPS WERE TIGHT. SLEEVE SECURED.