iXpand 256 GB not working with iphone 7 plus

[mrgalaxy]

I found the solution - there are 3 programs in the Apple App Store with almost identical names and look/feel - the two I had downloaded that came up first in the search when I plugged in the 256 GB Sandisk iXpand were not the right programs even though they looked like the pictures on line…  I later plugged it into my ipad and when it took me to the app store, the correct (and different program) appeared in the search results.  Once I download it, it all worked - that probably explains why so many people have this issue - there are several programs with similar names!