I wanted to start a new article and once I opened it (a location in this case), the article broke down. This happened several times.
The error occurs every time I enter Aradeia (my current world) and open an article or try to write a new one. I will add the picture with the error message for reference.
So, apparently, this error message does not appear when I access my account via IPad/Safari. I prefer writing my articles on my laptop, but for the time being, I will edit my posts on here, so i can continue participating in the challenge.
Nevermind, it now happened on my IPad as well :(
New update:
If I do not open the document in the new editor, but look for the file in the articles list and immediately open it in the old editor via the three dots, it somehow works.