As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: NOTIFIED BY GATE AGENT UPON LANDING THAT EXTERIOR HANDLE IS "OPEN" ON DOOR 1L. THIS EXPLAINS VIBRATION IN DOOR 1L DURING FLIGHT REPORTED BY FLIGHT ATTENDANT. REMOVED AND REPLACED SPRING INSIDE HANDLE SHAFT AT DOOR 1L PER AMM 52-11-11.