Do you use Mailgun to deliver emails from your WordPress site? Does it annoy you that email addresses using the Mailgun domain causes Contact Form 7 validation to fail? This plugin allows email addresses using your site’s Mailgun domain to pass Contact Form 7’s form validation feature. It also includes the cf7_mailgun_domain filter you can use to modify the default mailgun domain. Example: /** * Filter the Mailgun domain. * * @param string $domain Your mailgun domain; defaults to 'mg.your-site.com'. * * @return string Your mailgun domain. */ function my_custom_mailgun_domain( $domain ) { $domain = 'mg.my-site.com'; // Replace this with your Mailgun domain. return $domain; } add_filter( 'cf7_mailgun_domain', 'my_custom_mailgun_domain' );