As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, CREW RECEIVED A LANDING GEAR DISAGREE MESSAGE AND THE GEAR WOULD NOT RETRACT. CREW RETURNED TO DEPATURE AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE NLG SHOCK STRUT UNDER SERVICED. MAINTENANCE SERVICED STRUT SERVICE AND PERFORMED STRUT EXTENSION AND RETRACTION CHECK IAW AMM AND OPS CHECKED GOOD.