ERROR 1698 (28000): Access denied for user 'root'@'localhost'
I've got a similar issue, the solution:

0. login to MySQL

$ sudo mysql -u root
use mysql;


1. Change Password

UPDATE user SET authentication_string=PASSWORD('yourpass') WHERE User='root';


2.Change Plugin

UPDATE mysql.user SET plugin = 'mysql_native_password' WHERE User='root';


3. Finish It

flush privileges;
exit




Extra info

If you get errors like: "ERROR 1819 (HY000): Your password does not satisfy the current policy requirements" you can view the password rules with:

SHOW VARIABLES LIKE 'validate_password%';