Hard to say what is causing that problem.
You could try upgrading to Windows Live Mail, and see if that
cures the problem:
http://get.live.com/wlmail/overview
--
Gary VanderMolen, MS-MVP (Mail)
"Joe" <Joe@discussions.microsoft.com> wrote in message news:73FA614A-E5F7-496B-B62A-B613C9DCF987@microsoft.com...
>I am having a problem sending mail to only one domain name. If I send mail to
> this domain name using another computer which runs Outlook 2007 they get it.
> They don't have any spam filters of block my domain name.
>
> Could this be some sort of certificate problem. This problem started after I
> was poking around with digital certificates??? I don't think the domain name
> that I am trying to send to requires a digital certificate.
>
> I don't even get an NDR from the other domain name.
>
> I even tried creating a new Wmail setup and it still didn't work.