paged navigation problem

I know, there are quite a few topics with this kind of problem, but I don’t find a solution for me.
I use wordpress as a cms and everything works fine except the pagination of the news-category.
The link https://www.baustelle.17hippies.de/hiplounge/news/page/2/ leads to the 404-site.
On root level it works fine: https://www.baustelle.17hippies.de/page/2/ leads to the 2nd page of the post-archive.
I use the pagebar2-plugin, but it makes no difference if its on or off.
The permalink-structure is /%category%/%postname%/. If I switch it to standard it seems to work, but I want it with my permalink-struktur and not like this:
https://www.baustelle.17hippies.de/hiplounge/?cat=3&paged=3

Any idea where to look? Thanks.