Setup proccess failed. Access denied for user 'root'@'localhost'

Hi, I am trying to setup froxlor on my Debian LAMP. I followed the guide from here: https://github.com/Froxlor/Froxlor/wiki/Install-froxlor-on-debian and and here https://github.com/Froxlor/Froxlor/wiki/Install-froxlor-from-tarball. I am stuck on page that I need to provide credentials to the database. When I go forward I do get this: I fill in my credentials; new password for froxlor database, new password for admin account, my root password that I can use to login locally via:
Newer distros do this to avoid usage of the root user, to allow login run the following queries: update mysql.user set password=password('YOUR_MYSQL_ROOT_PASSWD') where user='root'; update mysql.user set plugin='' where user='root'; flush privileges;