Body Class is only applying on main-page.php and not on list-page.php

prob.php

<?php

//* Add custom body class to the head
add_filter( 'body_class', 'sk_body_class' );

function sk_body_class( $classes ) {
	
	if ( is_page_template( 'list-page.php' ) || is_page_template('main-page.php') || is_archive() )
		$classes[] = 'masonry-page';
		return $classes;

}