As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF FROM IAD GEAR WOULD NOT RETRACT, BOTH SYSTEMS TRIED. FOLLOWED ECAMS. RETURNED TO IAD. REMOVED AND REPLACED PROX BOX PER MM 32-31-71, OP'S GOOD. PREMATURE REMOVAL/INSTALLATION OFF MFG 8-371-01A. SERVICED LT LANDING GEAR BOGIE BEAM DAMPER PER MM 12-12-32-0.