As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT CREW REPORTED SWEATY SOCK SMELL FROM FL220 TO BLOCK IN. MAINTENANCE FOUND THE APU OIL COOLER LEAKING OIL AND THE APU INTAKE PLENUM SATURATED WITH OIL. MAINTENANCE REPLACED THE OIL COOLER O-RINGS PER AMM 49-91-44. A DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYSTEM WAS ACCOMPLISHED PER TASK CARD 26L00021014 ALONG WITH A SATSISFACTORY LEAK / OPERATIONAL CHECK WITH NO ODORS REMAINING.