Backend "Publish" Side Menu is missing

Hey there!

My website https://www.inshot.at has been working like a charm lately, but in the backend on one specific page (https://www.inshot.at/inshotbox/) the menu on the right hand side called “Publish” is missing.

I can type in new content, do changes to the already existing one but can’t save and publish my changes.

Do you have a fix for me?

Cheers!