As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURNED, AFTER TAKEOFF, GEAR LEVER COULD NOT BE RAISED. COMPLIED WITH QRH AND LANDED AT DEPARTURE. AFTER ENGINE SHUTDOWN EICAS MSG "LG NO DISPATCH" DISPLAYED AND THEN EXTINGUISHED. R & R RT MLG DOWNLOCK 2 PROX SENSOR IAW AMM 32-61-07. PERFORMED LANDING GEAR SYSTEM OPS CHECK OF LANDING GEAR EXTENSION AND RETRACTION IAW AMM 32-33-00-710-801-A500. ALL CHECKS NORMAL AND SATISFACTORY.