change or add username and password for session/database

Hello, I tried multiple times to change the root to another username and set a password, but each time I try to open the session it says your access is denied and the Password is set to 'YES', check the screenshot in the attachment.

any ideas? thanks in advance

The message "using password: YES" does not mean the password is "YES". It means the password used is not empty.

How are you trying to "change the root to another username and set a password" ? Because that has to be done in Wordpress, not Heidi.