post link broken

I’m running an imbalance child theme on
http://koepelfortasperen.nl/

Yesterday I added the flickr photostream plugin and updraft plus, which both work fine. However, my links from the post cover images on my home page are broken, leading to “sorry, but you are looking for something that isn’t here”.

I have tried deactivating the new plugins, but no change. I also made a new post which had the same problem.

Any ideas?