First, to check what is being used run this,
SELECT user, authentication_string, plugin, host FROM mysql.user;
If the user you are having issues with is set to auth_socket then you may need to change it to method with mysql_native_password
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
Change root to the user you need and set the password to whatever the password is supposed to be.