Without speaking Dutch, when I read Windows Defender, I knew that it is the reason why you are not updating.
https://www.maketecheasier.com/perma...er-windows-10/
Have a read at that article, more importantly the Regedit part where you can completely disable your AV from working using registry keys.
Alternatively you can download MBAM if you are scared of being infected/hacked, good luck.