As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE AIRCRAFT WAS AT 19,000 FEET WHEN A EXTREMELY LOUD SQUEAL WAS HEARD BY THE PASSENGER DOOR. AIRCRAFT MADE AN UNSCHEDULED LANDING. MAINTENANCE INSPECTED AND ADJUSTED THE PASSENGER DOOR UPPER FOLDING FLAP. AIRCRAFT WAS PRESSURIZED AND LEAKED CHECKED GOOD.