Same problem here with an iPad Air 2. I'm a rookie when it comes to this stuff. I plugged it into my MacBook Pro and ran the Arturia apps included with it - no problem.
However, using the camera connection kit and one of the Arturia apps, or Garageband, or "Tabletop" (I have no clue what this thing does - it has a bunch of different modules but I have no idea what they're for) absolutely nothing happens when I open an app and then plug in the iPad. No error message, no lights, no sound - not a thing.
I've searched this forum and found nothing, nor is there anything in the manual (even though on the box and in advertising it's apparently supposed to work).
I got it specifically for the iPad so it's useless to me otherwise. Can someone point me in the right direction to get this thing working?