As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) UPON LANDING THE CREW NOTICED THAT THE NLG DOORS OPENED BUT THE GEAR DID NOT RETRACT. THEY PERFORMED THE EMERGENCY RETRACTION WITH NO ISSUES AND LANDED WITH NO ISSUES. AFTER TROUBLESHOOTING, FOUND THE NLG SELECTOR VALVE FAILED. A NEW VALVE WAS INSTALLED AND SATISFACTORY GEAR SWINGS WERE PERFORMED.