Permissions required to use CRM iPhone App

Hello,

We are using CRM online version 2015 with Update 1.  Four of us have the CRM app installed on our iPhones and it works great!  The app version is 3.0.0.69.0 (1,1).

But nobody else can get logged in completely.  It gets to the point where 2/5 of the updated customization's are downloaded and then it stops with the error "We're Sorry - Something went wrong while initializing the app.  Please try again".

The difference is that the four of us who the app does work for are CRM System Administrators.  My test user works fine if I add him to the CRM role System Administrators ... but when I remove him from that role the app stops working.

I'm sure this is a permission issue ... I just can't find what permission is required.

Thanks,

Terry