I have been having the same issue, but with an 7th generation iPad. Have you gotten any help with this?
I got both my iPad and Smart Keyboard brand new, less than a month ago. The iPad works like a dream, but I couldn’t get it to recognize the Smart Keyboard. After wasting over 2 hours trying to get the keyboard to work, I set up an appointment at the Genius Bar. I honestly figured they’d have to replace it for me.
Even with the appointment, I had to wait another 15-20 minutes. While I waited, I opened up my iPad, and the keyboard still didn’t work. I literally sat down with the technician, and I’ll be darned: the freaking keyboard worked... for the first time EVER. I was completely baffled and thought it had to be a joke.
The keyboard continued to work when I checked a few times over the next half hour. Then when I get back home — less than two hours after my Genius Bar appointment — I try my Smart Keyboard and... same issue. It won’t recognize the device. I’ve tried all the suggestions: disconnecting and reconnecting it, cleaning the sensors, restarting the iPad. What is going on? This is extremely frustrating.