The web server in DMZ is not able to send mail to a distribution group in our Exchange 2010. I'm sure the receive connector has been set to allow delivery of internal emails from anonymous users with this command:
and from the log tracking I can see the email did get through the connector but then failed in routing to this distribution group. The error is:
550 5.7.1 RESOLVER.RST.AuthRequired; authentication required
What could be wrong? Could a distribution group be set up to only allow authenticated users to send mail? How to resolve the issue?
Please help. Thanks.