Jawbone UP api iOS, can't authenticate on non root view

Question

I'm making an app with the Jawbone UP API. The first root view controller is a tutorial about the app. I added the jawbone authentication code into the next view. But the web view is not showing. The web view is only showing when it is on the root view.

This is the code I used:

[[UPPlatform sharedPlatform] startSessionWithClientID:@"MY_CLIENT_ID"
                                     clientSecret:@"MY_CLIENT_SECRET"
                                        authScope:(UPPlatformAuthScopeExtendedRead | UPPlatformAuthScopeMoveRead)
                                       completion:^(UPSession *session, NSError *error) {
                                           if (session != nil) {
                                               // Your code to start making API requests goes here.
                                           }
}];

I don't know what I'm doing wrong. The code is correct in the root view, but not in the other view controllers.

Who can help me? I really need it!

EDIT: Here you can find the Jawbone SDK: https://github.com/Jawbone/UPPlatform_iOS_SDK/#add-the-sdk-to-your-project