Hanging at "signing in" with Adobe Enterprise ID

HI All,

We're having trouble with some of our mobile users. We have the Enterprise suite, and some mobile users get hung on the "signing in" screen when logging into mobile apps (e.g., lightroom) on their ipads. Users will enter their enterprise user id, hit enter, but the user never arrives at the login screen to enter their ID/password. They just get hung up on "signing in". This seems to be happening on ipad pros. All apps have been deleted and reisntalled. This is not limited to a single app. If a user has this issue, it's with all the adobe mobile apps. Any help would be appreciated. Thanks!

Todd