Ixpand usb 3.0 not working with Iphone 7

for the edification of anyone else who might come across this thread searching for an answer to this issue, I fixed this issue by deleting the ixpand app, turning off the phone, turning it on again and redownloading the app. Deleting the app and redownloading (without restarting the phone) didn’t work. And just restarting the phone without deleting and redownloading the app didn’t work. 

this issue being solved, I have to confess that the iXpand drive is the best money I ever spent since I bought an iphone. 

Now, if I could only work out why the phone says I have 22GB of photos, while the info pane for the iXpand drive says there is 20GB on the drive, in spite of the fact that the iXpand app said that my photos and videos were “fully backed up”…