I cannot remove a domain from Exchange server. I have a company who, let's say, run existingcompany.com as their main e-mail domain. They then decided they wanted to receive e-mails as newcompany.com (although not to send as that domain). I therefore added an entry under 'Recipient policies' for a new SMTP address to be applied to all users, and modified the MX records for newcompany.com. That all worked.
They now want to spin off newcompany.com onto a separate server, so I changed the default policy back to its old setting, and deleted all the 'newcompany.com' addresses manually from each user in SBS, and ran a gpupdate /force from the command line. However, I still cannot send e-mails internally to newcompany.com. They should exit the server, and go out to the Internet, but they just bounce back with 'undeliverable'. Is there something I'm neglecting to do?