@alexandregallot - don’t give up just yet.
I’ve been studying Arabic on here for 5 years and have never had this issue. When I clicked on your link it too wouldn’t work for me. However, if you click on the language option at the top of the webpage and change the language to English and then straight back to Arabic again it works fine. I know this is not ideal but it takes 2 seconds to do and is a work around whilst they are sorting the issue . Hope this helps. Jane