makes it look pretty likely that this is a problem on Steam's end.
In the meantime...
If you had a pre-Steam account on the Zero-K server, even if your account is linked to Steam now, your old password may still work. Go to lobby settings, untick "Login with Steam", and give it a go.
If you didn't have an account before Steam or have forgotten your password, get in touch with myself or another admin (easiest through Discord) to set a new password. This will unlink
your current account from Steam. When the issue is resolved, to relink your account retick "Login with Steam" in the lobby settings, and then log in with your existing user name.