I'm having the same issue as in this ticket: I set up eNewsletter to send to 23 people, but I'm the only one who received it (I called a few of them to be sure, and the stats confirm no one's opened the email).
The email I'm receiving at is within my BlueHost account. When I tried another email (hosted through Rackspace, I think, though it may be related to Gmail), I got nothing—same as the ticket referenced above. That ticket didn't seem to get resolved, so I'm eager to do whatever's needed. I won't be able to use the plugin in the future if we don't figure this one out.