As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT THE AIRCRAFT WAS UNABLE TO MAINTAIN CABIN ALTITUDE. THE FLIGHT CREW RETURNED TO POINT OF ORIGIN (MSP). THE CLAMPS ON THE RIGHT PACK BAY WERE FOUND LOOSE AND LEAKING. TIGHTENED CLAMPS AIRCRAFT PRESSURIZED AND OPERATIONALLY CHECKS GOOD.