ECAM 21.118.W - first start-up fails

Hello all,

we received our De'Longhi Magnifica S(ECAM 21.118.W) today and accordingly I wanted to use it directly today of course.

I did everything according to instructions, that is: water tank filled to max, container placed under the milk frother, turn on the device (indicator light is on), output knob for steam set to I...and that's it. No water comes, but only ~15 seconds a very loud sound and then the lamps for the error message "grind too fine (...)" and the lamp for descaling flash.
The same sound comes when I want to test the water flow in test mode. So apparently the machine is not drawing water. Someone has an idea how I can solve the problem? Or do I need to replace the machine?
I took out the brew group once and rinsed it.

Many greetings and thanks,

Jan