As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
1L DOOR NOT SEATED. UNABLE TO MAINTAIN CABIN PRESSURE. DEADHEADING CAPT INSPECTED DOOR, OBSERVED DOOR ROLLER OUT OF ENGAGEMENT WITH 1/2" TO 3/4" GAP AT TOP TO BOTTOM OF DOOR. RETURNED TO JFK. FOUND DOOR OUT OF RIG. ADJUSTED DOOR RIGGING, OPS NOW OK.