As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: LOST PRESSURIZATION AT 5000FT ECAM CABIN PRESSURE. SAFETY VALVE OPEN. AIRCRAFT DID NOT KNOW WHERE IT WAS ON VERTICAL PROFILE. ECAM ALSO HAD AN AMBER OUTFLOW VALVE OPEN INDICATION. MAINTENANCE DETERMINED THAT THE OUTFLOW VALVE STUCK CLOSED WHICH IS WHY THE SAFETY VALVE OPENED AND REPLACED THE OUTFLOW VALVE PER AMM 21-31-51. A SATISFACTORY OPERATIONAL TEST WAS ACCOMPLISHED.