Q&A plugin: trying to edit a reply in the frontend gives an error 404

After adding an answer to a question, I get an "edit" link to edit the answer.

Following this link results in an error 404 - page not found. I need to edit the answer via the dashboard / backend.

I send you an example as screenshot attached

Any ideas?

Best, Wolfgang

PS: The header section of the plugin in the dashboard (see screenshot) looks kind of weird, too...