As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD FLT 5872 THE CREW REPORTED JUST AFTER TAKEOFF RECEIVED A AIR/GROUND FAIL MESSAGE AND THE GEAR LEVER WOULD NOT GO UP. MAINTENANCE INSPECTED AND FOUND A LOOSE CONNECTOR ON NR 1 WOW PROXIMITY SWITCH. TIGHTENED CONNECTOR AND OPERATIONAL CHECKS WERE GOOD.