Issues sending coupon notification to newsletter subscribers

I am having some trouble sending out a coupon notification to our customers who subscribe to our newsletter. I have created a coupon code and then when emailing it our to our newsletter subscribers it appears to be attempting to send out but then returns saying that it is unable to connect to the SMTP. I then checked our email archive and it appears its sending an email to about 12 out of 57 newsletter subscribers(me being one of them) and then stops.

Our website is currently being hosted on a godaddy server and after speaking to them yesterday it seemed like they were seeing a few emails go out but did not see any mass email like we had been trying. I searched through the forums and did find a page(http://www.zen-cart.com/wiki/index.php/Troubleshoot_-_Email_Problems) explaining how to setup your email depending on the different hosting plans and all our settings appear to be correct. The transport method is SMTP, mail host is relay-hosting.secureserver.net, and the mail server port is 25.

I was just curious if anyone else has experienced anything like this or if there would be any other suggestions that I could look into. Any feedback would be greatly appreciated. Thanks.