The registration as well as any login in the KVV.mobil app works through a link which automatically logs you into the app, to securely authorize your smartphone. However, this only works if you have access to the inbox of the e-mail address you registered with in the app in a standard e-mail program of your smartphone (e.g. Apple Mail/Gmail). Only then your e-mail address can be correctly identified. Once you have logged in, the login will remain permanently and you will not have to log in again every time you use the app.
You did not receive the e-mail? Please check your spam folder and make sure that the maximum capacity of your inbox is not exceeded.
You don't have access to your inbox from your smartphone? Alternatively, you can open the login e-mail from your PC or laptop in your browser. It will contain a QR code. You can scan this code with your smartphone and you will then be logged into the app.