Solved no categories shown in Kunena-menu after migraton Joomla 3->5

Hello,
I have migrated from Joomla 3 to Joomla 4 and after that to Joomla 5. After migrating I have installed newest Kunena and all Plugins, delete all menus pointing to Kunena, empty the trash and create the Kunena-menu via tools->menu-manager and "restore kunena-menu". Then activate the new Kunena menu in my main-menu. It is shown, but didn't work as expected.
By clicking on the menu I see an empty Kunena-Site without any categories. Statistics say that there are 10 categories, 194 topics and 496 articles. But I can't see any of the categories in Kunena.
I have selected all categories to be shown in the frontend-configuration:


See the resulting page here: testsystem.glodek-edv.de/index.php/forum    (site is in german)

What am I doing wrong?

best regards,
Siegbert
 

What happens if you only select the top item (show/ hide al categories)

it's exactly the same. No matter what I choose in catergory-list, nothing is shown on the site.

Perhaps the pages are not displayed because there are no members registered.

 

Statistics say that there are 10 categories, 194 topics, 496 articles and 459 members, see here: testsystem.glodek-edv.de/index.php/forum

Did you run Tools-Diagnostics?