I’ve just tried to send you a message from within your Royals site. The site gave me a “success” message confirming that kiwitrees did send the message. That was sent while I was logged-in to your site. I will now try another not-logged in.
That indicates the problem may be at your mail server.
A couple of questions:
Is the email address you have entered in your administration page (Administration > Site administration > Site configuration > Mail configuration tab) agains “Sender email” a correct and valid email address? Many email servers object if it isn’t.
Have you and your cousin both checked your mail spam / junk folders ?
Are there any corresponding error messages in your webserver logs? It would be unusual if there are none, if the mails were not sent.