So I tried to restore locally and it didn't work. Made me think maybe the apk I had backed up on Dropbox, which was the most recent update one, was messed up somehow. That and it kept asking for pro version sometimes and sometimes it wouldn't. Anyways, I downloaded a new copy from your site and it restored beautifully. Thanks again for such an awesome app.
I am also having this issue. I have a new S7 and it will not restore. I also tried a Nexus 5x and the same thing. S7 is running 6.0.1 and nexus is running 6.0.1. I tried a few of the restore files that i have an nothing will work.

I downloaded the latest APK today... 9.4.5

I tried adding some info manually and then tried to back it up locally and fails the backup. Error backing up data. Try again.