I've been poring over the forums all day trying to find a similar problem and not really finding exactly what I need.

I've got about 50 websites built with 5.2.3 and the Newsletter works on some and not others, while they appear to all be configured the same in the host settings.  Here's my scenario:

SMTP host settings are set to my mail server (dedicated server at 3 Essentials) mail.domain.com, Authentication is Basic, SMTP username is admin@domain.com, and the mail accounts password.  SMTP test sends successfully.

In the Newsletter module I check the role to whom I emailing, 'test' in this case with 4 users all internal to our organization.  BCC:  is selected and sending is asynchronous.  I send and the module says sent successfully, I get a SMTP Configuration Test, since I'm the host email address (don't get these when its successful) and the Bulk Email Report that I get from the admin of the site says:

There is a problem with the configuration of your SMTP Server. Mail was not sent. 

If I add my email address to the additional email list, I do get the email.  So it goes out to individual email addresses but not the roles.

As I mentioned I just moved all of my sites from iHost to 3 Essentials, some work and some don't.

Any advice would be helpful.

Thanks,
John

Sorry I missed that part in my scenario.  Both From: and Reply To: are admin@domainmname.com.

I've tried changing this from hostadmin@hostdomain.com to admin@domain.com and it made no difference.  I've copied all settings from one domain's host settings that does work to the one that doesn't work, with the exception of the domain names, and it still won't work.  All mail is hosted on the same server so the mail server settings should be the same, I think.

Thanks for the ideas Sebastian, I'm just at a loss.

~John