As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR 5537 - STL - DOWNLOCK RELEASE WILL NOT MOVE TO RETRACT LANDING GEAR FOLLOWING TAKEOFF. MAINTENANCE INSPECTED AND CLEANED ALL 4 WEIGHT ON WHEEL PROXIMITY SENSOR, REMOVED AND REPLACED A BAD PROXIMITY SENSOR ON LEFTHAND MAIN GEAR PERFORMED GEAR SWING, OPS CHECK GOOD.