As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WARNING MESSAGE GEAR DISAGREE AND NOSE DOOR OPEN DURING TAKEOFF.RECYCLING OF THE GEAR WAS TRIED UNSUCCESSFULLY, AIRCRAFT RETURNED TO YUL FOR LANDING. AFTER INVESTIGATION, FOUND PROXIMITY SENSOR BRACKET DEFORMED. BRACKET CHANGED AND PROXIMITY SENSOR ADJUSTED AS PER MAINTENANCE INSTRUCTION MANUAL MM 32-61-05. GEAR SWING CARRIED OUT, CHECK SERVICEABLE.