ugurkirbac

It solved the problem Thanks a lot.
This is the code for whom might have the same problem.

$args = array(
	'post_type' => 'event',
	'tax_query' => array(
		array(
			'taxonomy' => 'event-categories',
			'field'    => 'slug',
			'terms'    => 'featured',
		),
	),
);