Finally I got into the setup. With this done I was asked to enter passwords for admin and root.
I tried several pw´s (even 1234), but I´m still unable to log in as admin(!).
On the other hand I´m able to log in as root, no problem.
I suspect that you are trying to use the admin user & password from the console. This will not work.
The admin user is specifically for logging in to the Web User Interface (WUI) via your browser and not via the console.
The root user is only for logging in via the console and not via the WUI.