As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MIA - INFLIGHT T896/26 AFTER TAKEOFF ECAM INDICATED GEAR RETRACT WARNING. UNSAFE GEAR RETRACTION. AFTER GEAR WAS SAFELY DOWN AND LOCKED RECEIVED LANDING GEAR RETRACTION INOPERATIVE MESSAGE. RETURNED TO MIA AND LANDED WITHOUT INCIDENT. PERFORMED BITE TEST OF PROXIMITY UNIT. NO FAULTS NOTED. CLEANED PROXIMITY DETECTORS ON RIGHT AND LEFT MAIN GEARS. REPLACED PROXIMITY DETECTOR UNIT AS A PRECAUTION. SYSTEM GROUND CHECKED NORMAL OPERATION.