I have exchange 2003 sp2 and added a new domain in the recipient policy. I have three domains i accept email for. The original 2 are fine. The new one i just added gives me an error when i send email to a user i get The message cannot be delivered to the following address. ---
firstname.lastname@example.org Mailbox unknown or not accepting mail.
550 5.7.1 Unable to relay for email@example.com
The user has an email account for them in AD and they can recieve mail from the other domains. I have re-started the exchange box to "force" an recipient policy update and still get the same error