We are trying to mask our email address and unify it with the company address. I do it by setting the primary SMTP address to UserID@company.com in the Exchange user config. Keep the UserID@email.site.company.com as a (non-primary) SMTP address.
It works with all the employees in our site. However, I'll get the following error when I send email to people in headquarter, whom do not have an account on our Exchange server.
Your message did not reach some or all of the intended recipients.
Subject: Test 7-1-2010
Sent: 7/1/2010 10:11 AM
The following recipient(s) cannot be reached:
'John Smith' on 7/1/2010 10:07 AM
The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address. [exchange2k3.email.site.company.com][/exchange2k3.email.site.company.com]