As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN ALT WARNING MESSAGE POPPED UP AND BOTH PILOTS GOT ON O2. COMPLIED WITH PROCEDURES (MEMORY ITEMS, QRC, QRH.) LANDED UNEVENTFUL. (FLIGHT 5956 - FILED CLOSED)CLEANED AND STOWED BOTH PILOT AND COPILOT O2 MASKS, CREW O2 PRESSURE OKAY FOR DISPATCH