Kobo is "Connected and charging" but ADE doesn't detect my kobo

Just got a used Kobo Glo HD off marketplace, all looks well. Except when I plug it into my macbook through a dock (because Macbooks don't have USB ports), the kobo detects that a computer is connected and charging, but the Mac nor ADE detects a kobo connected. I've factory reset the kobo, tried a different cable, tried a different port on the dock, software update the mac and ADE to the latest edition, reset the USB port, tried a different computer, and completely out of ideas at this point! Any one else have this issue?