Help wiht an iPad Mini Appearing in Digital Editions

In digital editions on my Acer computer, I can't get my iPad mini to appear as a device. I have authorized it to the same account as my computer. My Kobo still appears a device. I don't think I have too many devices authorized, I did not receive an error message and I tried to confirm with Customer Support, but I did not get answer. Does anyone know how to fix this?