I hope someone has more information that the provided info on Microsoft site. The issue is as follows.
We have removed one FQDN from it joint domain and created a new domain for our client, successfully splitting it into two separate companies. While our systems work great by them selves, we are having issues with the outlook not accepting Emails from the original domain. We can send emails to the original domain from the "child" domain, but can not send to the new domain from the original. The IP address and FQDNs have been checked with anti-abuse.org. We did find that one of our IPs seem to have some list on spam and barracuda but I thought that would be a blanket block. We are able to send to anyone else from either site, but simply can not communicate between those two domains. Any Ideas?