BuddyPress.org

I have created several forums for groups. And one group forum i have set as the category (groepsforumz in my video), while the others are all children of that category.
It’s all set up as in this page https://codex.buddypress.org/getting-started/installing-group-and-sitewide-forums/

The strange thing is, that this overview with forum is only working when i am logged in as an administrator and it produces an error when i am logged in as a member user.

Is there some setting I have missed?

Please have a look here for a screencast:
https://screencast-o-matic.com/watch/cFQXjdqGKI