Recently, I added an edge transport server in the dmz. This server was configured using edgeSync and all the connectors were added successfully. I can test synchronization by using test-edge... cmdlet and I can verify the accepted domains as well. So I know its working fine...
I can receive email from the outside world, which is picked up by the edge server and forwarded to the hub for delivery. That works well. On the other hand, when I try to email an external email, the hub transport forwards it to the edge, and there, it remains in queue. The error that is being generated is:
451 4.4.0 Primary Target IP address responded 421 4.2.1 unable to connect. Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts or delivery failed to the all alternate host.
If I manually add a (internet) send connector on the hub transport server, I can email directly from the hub server, but I do not want to do this. I have both of the servers added in each of the hosts file and dns works fine. I have logging enabled if anyone wants to view a specific log.