As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DIV - DURING FLIGHT CREW WAS UNABLE TO MAINTAIN CABIN PRESSURIZATION. DIVERTED TO PIT. MAINTENANCE PRESSURIZED AIRCRAFT AND FOUND APU PNEUMATIC DUCT LEAK. APU BLEED DUCT AT AFT P-DOME INSTALLED BACKWARDS NOT ALLOWING DUCT FLANGE IN LOCATION FOR SEAL CLAMP. REMOVED AND REINSTALLED PNEUMATIC DUCT PER AMM. OPS CHECKS GOOD, AIRCRAFT RETURNED TO SERVICE.