Savings Banks app displays rooted device. SuperSu does not say rooted, Huawei p9?

I downloaded the Sparkassenapp and the associated PushTan app today. When I open the apps, I'm directed to the Sparkasse website, which has a warning because my device is supposedly rooted. I bought it new then and never did it. However, the SuperSu app with which you can root or redirect the phone on Android devices says that the phone is not rooted at all. What should I do to make the apps work?

The phone has the latest operating system installed, downloading the apps again did not work as well as restarting the device.

That can have a thousand reasons. Write to the developer of the app, which should help you the fastest.