Get the password for the debian-sys-maint user. Just
and get the password.
and enter the password you got in the previous step.
Once on the MySQL shell, you can define the password using
where new_root_password is the new password for the root.
If there are no root entries, or if you’re still getting problems logging in using root, grant all the privileges to the root user:
where, again, the new_root_password is the new password for the root.
This should do work and now you can
and enter the new password you’ve chosen for the root.