These steps only needed to be done for one time only. If you have trusted the app before, you don't have to go through these steps again.
Whenever you get this prompt after installing {{config.name}} app, click "cancel".
Go to ios settings page.
Click on "Device Management"
Under "Enterprise Apps", there should be an enterprise app
In this page, you should see "{{config.name}}" app. In order to use this app, please click on the trust button
Upon getting this prompt, click "Trust". After trusting, you may now go to the home screen and click on "{{config.name}}" app again.