Mysql (adminer) : error "Access denied for user 'root'@'localhost'(using password :yes)

•  Server

 ubuntu 18.04LTS

• Mysql 

mysql-server v5.7

• Error: 

• edit mysql config file

sudo nano /etc/mysql/my.cnf

• Add to my.cnf

[mysqld]

skip-grant-tables

• restart mysql

sudo systemctl restart mysql

• login to mysql and run command

$ mysql -u root 

UPDATE mysql.user SET authentication_string=PASSWORD('YOURNEWPASSWORD'), plugin='mysql_native_password' WHERE User='root';

exit;

• disable the added lines from my.cnf

#[mysqld]

#skip-grant-tables

• Restart mysql 

sudo systemctl restart mysql

• Run mysql_secure_installation and set 'y' for all options

sudo mysql_secure_installation

• check login to mysql 

mysql -u root -p  

Now login to mysql as user root with new password must be possible.