Multisite blogs shows another blog on the network

I have a big issue on my multisite.

People can create their own blog on my site, as it is a blognetwork. But some of the users experiences that their blog shows another blog on the network, and not their own. It is still their domain, but not their content on the site.

I have had the same experience, but thought it only was me. Now it is a really big problem, because the users experience it too.

It is not on all the blogs, but some of them, and the problem come and goes.

If you look at the attached picture, you can see i have entered the url:, but it is not the blog i am seeing, it is a blog named "zigzag" (

I really need some help here.