As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEN - FLIGHT 4203, ON TAXI RECEIVED A "ANTI-ICE DUCT" WARNING. RETURNED TO THE GATE. MAINTENANCE CYCLED THE CIRCUIT BREAKERS AND PERFORMED A ENGINE RUN WITH ANTI-ICE OPERATING. NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.