I have set up a Edge role server in a DMZ. I can see that the edge server is recieving emails but then they stay in the queue with the following error: 451 4.4.0 Primary target IP address responded with: "421 4.2.1 Unable to connect."
I am able to telnet from the edge server to the hub server and vice versa on port 25. I have disable the firewalls on both servers and still the emails are stuck in the queue.
Any help would be greatly appreciated.