As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEN - DURING CLIMB THE CREW REPORTED BLEED ONE AND TWO TO BE INOPERATIVE. THE AIRCRAFT RETURNED TO DEN WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE CLEANED BOTH BLEED AIR VALVE FILTERS, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.