Can't login, though password is correct

Hi guys,

and again. One problem seems to pop up, once another has been solved.

So, I edited my themes function.php in order to restore my login page, which was broken-linked. I restored the function.php back to normal.

Now I’m stuck on the main wp login to my admin panel. Though username and password are correct, it won’t let me log in. “Username/Pswd wrong”

I tried to reset the password via email reset. I already tried setting the password temporarily in the function.php. I also tried to add a string to config. (all restored since it didn’t work).

I also tried to delete all cookies and stuff. And I already tried renaming the plugin folder temporarily.

Any more hints on this? Help is much appreciated! Thank you in advance.