As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EWR/IAD - FLT 6371 - DURING THE INITIAL CLIMB-OUT PHASE OF THE TAKEOFF, THE LANDING GEAR WOULD NOT RETRACT WHEN SELECTED UP. AIRCRAFT RETURNED AND LANDED AT EWR WITH NO FURTHER INCIDENTS. MAINTENANCE RESET THE LANDING GEAR AND FLAP EMERGENCY SELECTOR VALVES. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (X)