As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: INBOUND FLIGHT ATTENDANTS DESCRIBED A HEAVY ODOR OF DIRTY SOCKS DURING THE FLIGHT. THE OUTBOUBND FLIGHT ATTENDANTS HAD HEADACHES AFTER 10 MINUTES IN THE AIRCRAFT AT THE GATE AND THE AIRCRAFT WAS REMOVED FROM SERVICE. MAINTENANCE FOUND THE APU OIL COOLING FAN LEAKING OIL AND REPLACED IT PER AMM 49-52-51. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ODORS NOTED.