As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF CREW SELECTED -GEAR UP-. GREEN LIGHTS AND MAIN GEAR DOOR IN TRANSIT LIGHTS REMAINED ILLUMINATED BUT GEAR DID NOT MOVE. CREW ATTEMPTED GEAR RETRACTION THREE TIMES WITH NO SUCCESS. MAINTENANCE REPLACED THE LANDING GEAR SELECTOR VALVE. OPS CHECK NORMAL AND NO RECURRENCE.