I have read Mailbox unavailable. The server response was: 5.7.1 Unable to relay for abc@xyz.com and all of the answers. I have added my IP address via
IIS-->Default SMTP Virtual Server-->Properties-->Access-->Relay restrictions just add or exclude >the IPs you care about, should resolve the issue.
but it still gives me the error as above. What am I doing wrong?
I'm using Windows Sever 2003 R2 and IIS6.