I installed 3 Exchange 2010 Server in my organization. the servers are on 3 sites conencted via VPN.
When looking at the queue on the hub, the messages are in que with message "451 4.4.0 Primary target IP address responded with: "451 5.7.3
Cannot achieve Exchange Server authentication."
On EMC Configuration->Hub Transport->Receive Connectors->Default Connector->Permission Groups the Anonymous users and Exchange server are enabled.
what else can i do to resolve this problem?