We have Exchange 2010 running on a single server for about 50-60 users. Most of them send and receive mail just fine, however a couple of them cannot receive messages from anyone outside the company. They can send ok but no email from a user outside our domain makes it in. I have run the Remote Connectivity Analyzer and it fails the inbound SMTP test with the following error: Message: Mailbox unavailable. The server response was: 5.7.1 Recipient rejected (R4). I have searched and found some information about setting SMTP to deliver to the IP address of the Exchange server but that does not seem to have made a difference. Any suggestions would be welcome.
Thanks,