Test Emails work – real emails don't

Hi,
I have my own server and test emails work with phpmail and external smtp options (on different servers) but when I create a newsletter and try to send it to the test email (again on another exchange server I run) the email never arrives.

I get a SUCCESS message but a load of errors

SMTP -> get_lines(): $data was “”
<br />SMTP -> get_lines(): $str is “220-host.mydomain.com ESMTP Exim 4.80 #2 Wed, 17 Jul 2013 13:37:13 +0100
”
<br />SMTP -> get_lines(): $data is “220-host.mydomain.com ESMTP Exim 4.80 #2 Wed, 17 Jul 2013 13:37:13 +0100
”
<br />SMTP -> get_lines(): $data was “220-host2.mydomain.com ESMTP Exim 4.80 #2 Wed, 17 Jul 2013 13:37:13 +0100