“Database Connection Error” upon install in Apache VirtualHost document root.. Why did this happen? [closed]

You need to set these too:

define('AUTH_KEY',         'put your unique phrase here');
define('SECURE_AUTH_KEY',  'put your unique phrase here');
define('LOGGED_IN_KEY',    'put your unique phrase here');
define('NONCE_KEY',        'put your unique phrase here');
define('AUTH_SALT',        'put your unique phrase here');
define('SECURE_AUTH_SALT', 'put your unique phrase here');
define('LOGGED_IN_SALT',   'put your unique phrase here');
define('NONCE_SALT',       'put your unique phrase here');

Please generate and copy from here and check again: https://api.wordpress.org/secret-key/1.1/salt/

Also double check if your database name, user name, and password is correct.