As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO MAINTAIN CABIN ALTITUDE. *S/D* DELTA P MODULE FASTENER LOOSE AND NOT COMPLETELY CONNECTED, AND RIGHT HAND PACK VALVE BIASED TO THE CLOSED POSITION, AND AFT OUTFLOW VALVE HAD LOW RESISTANCE. REPLACED THE CABIN ALTITUDE INDICATOR AND THE CABIN PRESSURE SELECTOR PANEL. OPS CHECK OK.