with the thank you page open, go to window -> Server behaviors, in the server behaviors list, double click the universal email server behavior to edit it.
click the envelope icon to set Email server settings.
make sure to use the relay-hosting.secureserver.net server as the email server and port 25.
the relay-hosting.secureserver.net that go daddy offers can often take quite a while to send the email, it may take a day for the message to arrive.