If you are getting the error "Wrong username/password. Access denied" while accessing the phpmyadmin from cpanel, try resting the password for the cpanel account and check.

If that do not works, you can try executing the below script

/scripts/grabmysqlprivs

If you are still having issues then the issue could be mysql password is not reset even if we reset the cpanel password.we need to update the mysql password for the user from the shell to that of changed cpanel password.

mysql> update user set password=PASSWORD("pass") where user='user';
mysql> flush privileges;