I've got the following type of error messages several times before with different but valid email addresses.
Any ideas? Thanks.
Your message did not reach some or all of the intended recipients.
Sent: 10/31/2003 9:36 PM
The following recipient(s) could not be reached:
'Foo Bar (firstname.lastname@example.org)' on 10/31/2003 9:36 PM
553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)