As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE MAIN DOOR SEAL FAILED IN FLIGHT & THE PAX OXYGEN MASKS DROPPED. PAXS DONNED OXYGEN MASKS WHILE CREW PROCEEDED TO DIVERT FLIGHT & DESCEND BELOW FL 120. AN EMER LANDING WAS DECLARED & THE ACFT LANDED WITHOUT FURTHER INCIDENT. R & R THE DOOR SEAL. LEAKS & OPERATION CHECKS WERE GOOD & THE ACFT RETURNED TO SERVICE.