If you are having a problem sending, try sending a message using the "Send Test Email" option at the bottom of the sending account page.
Still Not Receiving Email
If all the appropriate ports are open and you still are not receiving email, try sending to an email address outside of the domain that you are hosting on or that you are using to send through Gmail. Many self hosted sites can be configured incorrectly to send email to email addresses where the domain after the "@" symbol matches the URL of the site. For example, if my blog name is called blog.example.com and I am trying to send an email to firstname.lastname@example.org it may not be delivered properly. Try sending a message to another address not associated with example.com. For documentation on configuring your MX records using cPanel, follow this link: http://docs.cpanel.net/twiki/bin/view/AllDocumentation/CpanelDocs/MXEntry
Beware of Spam
The last and most common reason that email does not appear to be received is because it is getting marked as spam. Please double check your spam folder. If the message has left the SendPress Queue then it has been sent.