As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT TOOK OFF FROM DEN AND THE CREW REPORTED THE GEAR WOULDN'T RETRACT. CREW RETURNED TO DEN AND FOUND HYDRAULIC LEAK IN RT NACELLE. MX HAD REPLACED A FAILED LINE PRIOR TO THE FLIGHT. THE NEW LINE WAS FOUND TO BE LEAKING DUE TO A FITTING WHICH REQUIRED TIGHTENING.