Unable to access MySQL after it automatically generated a temporary password

Try this:

mysql -u root -h 127.0.0.1 -p
Enter password: (enter the random password here)

Ref:https://dev.mysql.com/doc/refman/5.7/en/data-directory-initialization-mysqld.html

Following this, you may reset your password using
ALTER USER 'root'@'localhost' IDENTIFIED BY 'new-password';