As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 3267 BOS-EWR DIVERTED TO BDL DUE TO THE FRONT CARGO DOOR MASTER CAUTION DOOR LIGHT ILLUMINATED IN FLIGHT. CONTRACT MAINTENANCE PERFORM OPERATIONAL CHECK OF DOOR AND SWITCH SEVERAL TIMES. MAINTENANCE RE-SECURED DOOR OPS CHECKED GOOD.