So I installed a modified Spotify app on my iPad Air 2n, iPhone 6.
After I downloaded it I had to trust the developer, everything was fine, it worked and I could open the app. But after some time I had to verify the app again.
Quoted for the apple support page I got this:
After you verify an app for the first time, your iPhone, iPad, or iPod touch must reverify the app developer's certificate periodically to maintain trust.
Ok that isn't that strange, so I try to verify the app again, but now when I click on Verify App he won't do it.
Example picture from the support site is exactly how it looks before and after I click on Verify App:
