I have a SBS 2011 server which we are using Exchange on. I have 1 user who is not able to receive external email. They are the newest user I have added. I do use a 3rd part MX level spam company and I added her address and this did not resolve it. I then shut filtering off totally and this did not resolve. I have tested ports and they are open. When running a mailflow test on exchange for this user I get an error. The service not available closing transmission channel. The server response was: 4.3.2. service not available. The other error is Server does not support a secure connection. I have updated the service packs and rebooted and I am still getting this error.
I do have multiple domains recipients for exchange and everyone is is getting external email except this user. I really thought it was going to be the spam filter but that does not seem to be the case.