As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER DEPARTURE THE FLIGHT CREW RECEIVED A FUSELAGE LIGHT ILLUMINATED. FLIGHT CREW RAN THROUGH CHECKLIST, CHECKED WEATHER CONDITIONS AND WAS VECTORED TO LAND. UPON LANDING AND RETURNING TO GATE, THE DOOR WAS CHECKED AND VERIFIED TO BE CLOSED. THE GROUND CREW APPLIED PRESSURE TO THE DOOR HANDLE MECHANISM TO ENSURE IT WAS PROPERLY LATCHED AND THE FUSELAGE DOOR WARNING LIGHT EXTINGUISHED. AFTER FLIGHT CREW SPOKE WITH MOC, THE ACFT WAS FUELED AND DEPARTED WITHOUT FURTHER INCIDENT.