The settings shown in plesk don't work properly in our environment because of our non-standard implementation, and the fact that we allow external DNS. Very few people have actually gotten them to work, and even then they usually have to forgo SSL because many mail clients don't like the fact the server identifies itself by its server host name, which doesn't match your domain name.
As I said above, please use your server's host name (johnny.heliohost.org, tommy.heliohost.org, morty.heliohost.org depending on the server you're on) for both of those host names, and the connection issues should go away.