404 error on existing page / Heroic Knowledge Base / custom post type

I am using the Heroic Knowledge base Plugin. This is adding a custom post-type for the articles. The summary page is found here:

http://noggle.online/knowledge-base/

with knowledge-base as slug.

However, when clicking on the article itself, it tries to open the article of this custom post type with the correct link:
http://noggle.online/knowledge-base/test3/

I get the 404 page not found error page when browsing to the articles.

This works with any other standard theme. So there must be something in the enfold slug/permalink/custom post types settings why this 404 error comes up here.

I dont know where to change anything on this topic?

Could you please help and show why this 404 page error appeards even if the page/post is there and it works in other themes?

Thanks & Regards,
Lars