As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLT-BUF - FLT 1223 - AFTER TAKEOFF, THE CABIN WOULD ONLY PRESSURIZE TO 1 PSI WITH THE OUTFLOW VALVE FULLY CLOSED. THE AIRCRAFT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED SEALANT FROM THE AFT GALLEY SERVICE DOOR FRAME AND APPLIED FILLER AS REQUIRED. THE AIRCRAFT WAS PRESSURIZED AND NO LEAKS FOUND AT ANY DOOR. (M)