Can't edit wiki page or create thread in forum

Hello, I can't edit the page https://trisquel.info/de/wiki/alle-anleitungen but https://trisquel.info/de/wiki/setup is editable with my account, for example.

I am also no able to create a thread in the forum. This issue exists since today, but I was absence for a while.

I get the following error message when previewing or saving:

Forbidden

You don't have permission to access this resource.

I tried to log out and in again and clearing Abrowser's cache.

regards