As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: THE SMELL OF ROTTEN EGGS IN THE AFT GALLEY UNDER LOW POWER SETTINGS. THIS OCCURS ON THE GROUND AND IN THE AIR WITH LOW POWER SETTINGS WITH THE APU OFF, LEFT AND RIGHT PACKS IN AUTO, WITH ISOLATION VALVE IN AUTO. COULD NOT SMELL IN THE COCKPIT. MAINTENANCE FOUND SOURCE OF ODOR TO BE DOOR SILL DRAINS. UNCLOGGED DOOR SILL DRAINS IAW AMM 38-31-00.