Our mail filter is blocking outgoing messages that should be NDR b/c the sender is blank. We don't want to allow blank senders through so we've got to figure out how to fill in his field. We have one Exchange server, one domain and no Edge Transport Server. Here's the troubleshooting that I've done:
- The External Postmaster Address has been set to mailadmin@domainname in the EMC under Organization Configuration>Hub Transport>Global Settings
- The address has been verified using Get-TransportConfig | Format-List ExternalPostmasterAddress
- The mailadmin address is tied to a mailbox of the same name and user account in AD of the same name
Thanks for your time and assistance.