AutomateWoo - Blacklist an email address or multiple emails based on domain

functions.php

<?php

// this filter was added in AW 3.6.0

add_filter( 'automatewoo/mailer/blacklist', function( $blacklist ){
	$blacklist[] = 'email@example.com'; // block a single email
	$blacklist[] = '@hotmail.com'; // block all emails from a domain
	return $blacklist;
});