Hopefully this is a simple fix!
I have an application server on our network which needs to send email via our Exchange 2007 server to external recipients. However, when I try to perform this function the process halts with the following error..
550 5.7.1 Unable to relay
I've re-tried the process using an internal recipient and the email message is successfully relayed.
I assume there's something I need to change in order to allow a domain member server to send email externally via Exchange, but for the life of me I can't find the settings required.
Any help appreciated!!