I having problem sending from my Exchange secondary email account. My primary SMTP email is firstname.lastname@example.org. I have added secondary SMTP email address email@example.com in active directory user object properties (under Email Addresses tab). When I send from this secondary email address from my outlook, immediately after I hit the send button, within the next second, I get a bounced message with the following error message:
550 5.7.1 Unable to relay for firstname.lastname@example.org.
What is wrong? Fyi, I am using Exchange 2003.