What is disabled by default is remote root access. If you want to enable that, run this SQL command locally:
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;
FLUSH PRIVILEGES;
And then find the following line and comment it out in your my.cnf file, which usually lives on /etc/mysql/my.cnf on Unix/OSX systems. In some cases the location for the file is /etc/mysql/mysql.conf.d/mysqld.cnf).
If it's a Windows system, you can find it in the MySQL installation directory, usually something like C:\Program Files\MySQL\MySQL Server 5.5\ and the filename will be my.ini.
Change line
bind-address = 127.0.0.1
to
#bind-address = 127.0.0.1
And restart the MySQL server (Unix/OSX, and Windows) for the changes to take effect.
if this not working. check the 3306 port.
sudo ufw status
run this command to enable port
sudo ufw allow 3306
restart mysql