Yes, it still largely works, but the web front end is broken. It works via apps or alternative frontends, for example: https://alexandrite.app/feddit.de
The main admin of feddit.de travelled abroad a few months ago and has since disappeared .
However, many communities have already moved to feddit.org because it is not foreseeable whether feddit.de will work again.
Here is A list of server known to run flohmarkt