It should be working normally. Please note that sending to some domains is problematic from the free servers due to lots of past abuse of the service. I know there are issues with hotmail, but gmail seems to be okay. Also, ensure the content-type header is present and set to text/plain, or it will not send.
If you are still having issues with this, please try to provide more details, such as:
1) How you are sending the emails (if you wrote the script yourself, post it. If it's part of a larger package like a CMS or whatever, say what package it is)
2) What SMTP server you are trying to use
3) What email account you are trying to send it to (just the provider is fine, so if you were sending to blah@hotmail.com, say hotmail.com)
Also, provide proof of license for the email marketing software from Interspire, which I'll verify with them. That is of course if you did indeed pay $495 for their software, cause if you didn't the suspension will stay permanently.