conection Flash drive iXpand with iPhone 6

Iwas wondering if you could help me out with my Sandisk Flash drive ixpand, I used it few months ago with no problem data from my iPhone 6 to the drive. I wish to do the same operation by plugging the drive in to my iPhone. The Sandisk app keep asking “ plug in yr iXpand Flash Drive to get started! (The drive is lighting so there is condition. Any idea ? 

Try plugging in the iXpand drive before opening the app on your phone. You should get a prompt  “iXpand Sync would like to communicate with the SanDisk iXpand Flash Drive  Ignore | Allow”. Tap Allow; this will open the app.

Remember though, not all data is transferrable, thanks to Apple not allowing access to certain files/formats.

there are 2 apps. make sure you are using the correct one. Also see the following link for some trouble shooting steps that may help.