We are running SBS 2003 Servers for two different customers and domain names for exchange. Normal email is fine if replying, sending, receiving or forwarding. The problem occurs when the clients try and receive emails from an automated mailing list from two of their suppliers. Its a normal mail that comes through if it is sent directly but if it is CC to them it never bounces or arrives. This scenario happens for both of them which are different places, companies and different domain names? If we do a normal email and CC it its fine but only on the automated lists it fails?
Is there a setting in exchange that blocks this. we are currently not running any Spam software on the email accounts or servers.