Sorry to hear you are having problems with the ARC app when using Andriod 7.0.
To date, I have only tried Apple iOS. In my case I have had 100% success with all variants of iphone and ipad that I had tried using the ARC APP. Well... except for cases were I have tried to use the pacer car function which has been a bit of a disappointment.. but the rest of the ARC app functionality has been truely amazing!
I am very interested in trying the Android app, too, and wonder what device you are using with Android 7.0 which is giving the problems?