Plesk Login: User and password are not matching for every account!

[TimLoes]

G'day everyone,

I'm having a problem with the login for Plesk and PowerPanel.
Since yesterday I am not able to login with ANY of my accounts. It is always saying, that the user and password didnt match.
So I logged into the MySQL database to verfiy the passwords, just to make sure.
But they are exactly how I used them. Even "root" is not working.
I do have this issue on my Plesk and PowerPanel login.
I changed some things on my SSHd yesterday. Shouldnt actually have something to do with Plesk. Right? I, of course, changed everything back already.

I got noooo idea anymore. I really would appreciate every possible suggestion.

Thank you!