Dear ftp.uni-kl.de mirror admins,
there have been reports that something with your Fedora mirror is not working as it is supposed to. 404s and/or slow. I see that the Fedora 21 update directory is still empty, so something with your sync seems broken. I have disabled (User_active) your mirror for now but you enable it again any time you want in MirrorManager. Or you can let me know and I can re-enable it again.
Adrian