As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED OF A PRESSURIZATION FAULT AFTER TAKEOFF TO 9500FT WHEN THEY ELECTED TO RETURN BACK TO MMUN FOR LANDING AND EVALUATION. OPERATIONS WERE CONTINUED PER MEL 21-31-1. 16NOV2021 - THE MAINTENANCE TEAM TROUBLESHOT AND REMOVED AND REPLACED THE AUTOMATIC CABIN PRESSURE SELECTOR WITH A REPAIRED UNIT. OPS CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE.