Do you experience problems during downloading?
Check your connection in Status and Interface settings window.
Use Test Server in Config > Servers.
We will probably ask you to do a test using only basic settings.
Do you experience problems during repair or unpacking?
Enable +Debug logging in the Status and Interface settings window and share the relevant parts of the log here using [ code ] sections.
OK. Then you should first focus on gettin an / any IPv4 newsserver enabled, meaning: no time-out. As soon as that works, proceed to IPv6.
So, fill out "newsreader3.eweka.nl" with 1 connection and no username/password (as you don't have that) as newsserver in SABnzbd, click on Test Server. That gives you a time-out, right? If so: solve that first. It might be your own firewall or your ISP blocking News / Usenet. So I would de-install and remove your Windows firewall (so not just disable it), reboot, and then try again. If that doesn't solve it, take your PC to someone with another ISP, and test there.