I got the new box, and I got it to work. While doing so I probably found out why the old box could not get internet connection as it happened with the new box also. Welcome - please wait - spinning circle - Connection error CS1002.
As soon as I disconnected my “newly” connected wlan router from the modem, the box got internet connection again (I didn’t think the connection error had anything to do with the router as I did not use the tv box for few weeks after connecting the wlan router). So somehow the wlan router that I got to get more stable wifi interferes with the dhcp/internet of the tv-box. Is there some ip range that I can’t or should not exclude from dhcp that the box uses by default? I need to have some static ip’s within the internal network but I don’t need all 255 of them of course.
Anyway I think I can re-vitalize the old box also now that the internet connection is most likely solved, what should I do with it?
Also kudos to UPC. Even though it seems it was not a faulty equipment this problem was handled swiftly with a replacement box, hopefully the solution may help others. Anyway I modified my modem settings and the wifi router settings to not step each others toes so to speak. I think everything now works as it should.