Cannot Add certain features to XWiki articles or edit Articles that contain any of these features

[IARI]

Apparently this happens if and only if I try to access the XWiki via https.
Since this changes the way the question is frramed and i cannot edit the original questino i reposted this here:

XWiki not editable via https

Our self-hosted XWiki (tomcat9, ubuntu) works fine as long as I access it via http. As soon as I log in via https, I can no longer edit articles that contain any non-trivial features such as for instance: tables Display of Code even infoboxes … basically anything that goes beyond the most simple text-formatting and requires some sort of macro. Whenever I try to edit a page containing any of these (or create a new page with any of these), and I try to save the article i am prompted with “A…