As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF ECAM HYD G RSVR LO AIR PRESS. ALL OTHER GREEN SYSTEM INDICATIONS (QTY AND PRESS) REMAINED NORMAL. FOUND GREEN SYS RESERVOIR AIR RELIEF VALVE STUCK OPEN. COULD NOT PRESSURIZE SYS. REMOVED AND REPLACED GREEN RES AIR RELIEF VALVE IAW AMM 29-14-33. FUNCTION CK GOOD. LO AIR PRESS MSG CLEARED.