As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT, AT 2 HOURS AND 30 MIN, THE FLIGHT ATTENDANT REPORTED A ROTTEN ODOR COMING FROM THE VENTS IN THE FORWARD 1ST CLASS, NEAR LAVATORY. THE AIRCRAFT WAS GROUNDED. FOUND A CLOGGED DRAIN FLOAT VALVE. REPLACED THE FLOAT VALVE IAW AMM 38-31-06.