As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTO PRESSURIZATION SYSTEM FAILED AFTER TAKEOFF. FLIGHT RETURNED TO MSP AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND INSULATION LODGED IN OUTFLOW VALVE WHICH WAS RESTRICTING MOVEMENT. REMOVED INSULATION AND REPLACED OUTFLOW VALVE ACTUATOR. OPERATIONAL CHECK NORMAL. AIRCRAFT RETURNED TO SERVICE.