I am unable to connect the HomePod to my Home WiFi

I bought a used, but quite new, HomePod 2 (seller lives in another city) and I am now not able to connect the HomePod to my own wi-fi at home. Following Apples procedures to do reset on HomePod 2 does not help and Siri just repeats that she cannot connect to internet…

I live in Oslo, Norway, and the the Apple support I have talked with by phone is evidently not able to solve the problem.

May someone here on this community be able to help me? 🙏

[Re-Titled by Moderator]