In some MySQL installation in Ubuntu. You cannot login as root because it is not configured to use mysql_native_password. In this post, I will teach you how to enable mysql_native_password.
Log in to MySQL via terminal with
sudo mysql -u root
Once inside MySQL, we will need to change the default plugin authentication to mysql_native_password and set a password for root.
mysql> ALTER USER [email protected] IDENTIFIED BY 'password'; mysql> exit
You can now login in MySQL as root using the password you set.
mysql -u root -p