As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: COCKPIT DOOR LOCK - INFLIGHT THE UNLOCK HANDLE TURNED NORMALLY HOWEVER IT WOULD NOT GO FAR ENOUGH TO BE ABLE TO OPEN DOOR. AFTER SEVERAL ATTEMPTS WE WERE ABLE TO GET DOOR TO OPEN. CLEANED AND LUBED LATCH PER AMM 52-00-00.