Send e-mail to external recipient by script running on Exchange 2013 server

Hi,

I have a PowerShell script which sends some reports to external user. Script is running on the Exchange 2013 server.

There is a Relay connector, which is working fine, I can send emails from scanners, etc. to external recipients.

The problem is, I cannot send e-mail messages to external recipients directly form Exchange server, I get this error:

"Mailbox unavailable. The server response was: 5.7.1 Unable to relay"

I see that when message is sent from the script it uses "Default FrontEnd" connector.

How can I change this behavior and send e-mail messages from script on the Exchange 2013 server successfuly?

Thanks.