Here are my Host settings:

SMTP Server and port: smtpout.secureserver.net:3535

SMTP Authentication: Basic

SMTP Enable SSL: False

I can run the “Test” and everything works fine.

When I go to the newsletter and try to send an newletter, only to single email addresses, the newsletter module say the email was sent but upon looking at the event viewer I see,

“Mailbox name not allowed. The server response was: Sorry, that domain isn't in my list of allowed rcpthosts.”

What gets me is DNN sends out an email just fine via the STMP settings in Host, but not the newsletter.

Any ideas?

The from address in the newsletter is valid. I can copy the email address and paste it into an outlook email and it works.

I'm suspecting right now:

a) You mail server is not allowing relaying for other domains (check mail server log if you have access). Your mail server needs to allow access to other domains other than your own (I assume you can send email mails to addresses featuring the website domain?)

b) You maybe running an earlier version of DNN whereby mails sent with the newsletter module get confirmed as sent, when in fact the oppersite is true.