As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT DECK DOOR DOESN'T OPEN USING DOOR HANDLE. MAINTENANCE FOUND STUCK WASHER INTERFERING WITH LOWER DOOR LATCH MECHANISM OPERATION. MAINTENANCE REMOVED WASHER, CLEANED AND LUBRICATED THE DOOR LATCH MECHANISM PER AMM 52-51-21.