Yes, it still largely works, but the web front end is broken. It works via apps or alternative frontends, for example: alexandrite.app/feddit.de
The main admin of feddit.de travelled abroad a few months ago and has since disappeared . The other mods couldn’t fix the errors because they don’t have the password for the server administration.
However, many communities have already moved to feddit.org because it is not foreseeable whether feddit.de will work again.