Section Block has stopped working in back-end

Hello, as I’ve said before, I am a big fan of the plugin.

Sadly, now the section blocks have stopped working for me in the back-end. On the front end, everything seems fine, but when I try editing them, I get the following error: “In this block, an error occurred and a preview is not possible.” I can still adjust elements inside the sections, but whenever I click on a section itself, it and the contents of the section disappear and the error pops up.

Do you have any ideas what I can do to fix it? Is the section block maybe reacting to another plugin? I would really appreciate your help!

All the best!

The page I need help with: [log in to see the link]