As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 3264 - DIV - TO ATL DUE TO PRESSURIZATION ISSUE. OUTFLOW VALVE NOT RESPONDING TO COMMANDS. CORRECTIVE ACTION: OUTFLOW VALVE FOUND JAMMED WITH INSULATION DEBRIS. INSULATION REMOVED BUT STILL FAILED OPS TEST. REPLACED OUTFLOW VALVE. AIRCRAFT RETURNED TO SERVICE. (9654072)