iXpand isn't recognised by the app

I bought the iXpand Flash Drive 128GB 2 days ago and haven’t used it yet. I downloaded the app- SanDisk iXpand Sync- the drive appears on my Mac Pro but when i plug it into the the iPad Air and the iPad 4 and it won’t show up in the app on either devices. 

I can’t update the firmware unless I have it connected to the app.

What can I do? 

Thanks 

on the iOS device check Settings > General > About and scroll down. If you do not see the iXpand drive listed you may need to update the FW. To update you will need an iOS 8 device or a PC. See the FW update info below. 

http://kb.sandisk.com/app/answers/detail/a_id/17496/ 

If the iXpand is not listed here it may be defective. COntact sandisk support to check warranty status.