There is a simple solution.
MySql 5.7 comes with anonymous user so you need to reconfigure MySQL server.
You can do that with this command
try to find temp pass:
grep 'temporary password' /var/log/mysqld.log
then:
sudo mysql_secure_installation
On this link is more info about mysql 5.7
https://dev.mysql.com/doc/refman/5.7/en/linux-installation-yum-repo.html