WPJM: Send an email to employer when their job is approved.

functions.php

function listing_published_send_email($post_id) {
	if( 'job_listing' != get_post_type( $post_id ) ) {
		return;
	}
	$post = get_post($post_id);
	$author = get_userdata($post->post_author);

	$message = "
	  Hi ".$author->display_name.",
	  Your listing, ".$post->post_title." has just been approved at ".get_permalink( $post_id ).". Well done!
	";
	wp_mail($author->user_email, "Your job listing is online", $message);
}
add_action('pending_to_publish', 'listing_published_send_email');
add_action('pending_payment_to_publish', 'listing_published_send_email');

Hello Dan I addded this code to my functions.php in theme but it isn't sending any email.
Why?