Exchange 2007 Error Message - "Client not authenticated"
The Hub Transport server is set for authentication out-of-the-box. It’s role was not really designed to be outward facing towards the WAN. For AppRiver to deliver mail to a client with a Hub transport server, you need to set your Receive Connector to allow anonymous access.
The SMTP logs of a test message from AppRiver's delivery server to a Hub Transport server, which has not turned anonymous access on, will return the standard Client not authenticated message. Many Admins do not know how to fix this problem.
06:11:21.0161 DEQUEUER  SMTP(siig.cn)email@example.com failed: return-path address <> rejected by siig.cn:\r\n 454 5.7.3 Client was not authenticated.
1. To alleviate this problem, please use the below command:
set-ReceiveConnector -identity “Default SERVERNAME″ -PermissionGroups AnonymousUsers
Note: Replace SERVERNAME with the actual name of your server.
2. This command must be run in your Exchange Management Shell (EMS), which is located in the Receive Connector Properties page.
Note: The shell is basically a command line interface for Exchange.
3. Restart the SMTP services.
4. There is no specific SMTP service similar to Exchange 2003 and IIS. If you’re just trying to stop the listening Port 25 for Inbound/Outbound mail, then you must stop the Microsoft Exchange Transportservice.