Today I had a exchange server all the sudden that stopped sending and receiving e-mail and nothing has changed on it. When I attempt to send e-mails to it I am getting the following NDR message:
SMTP error from remote mail server after RCPT TO:<staff@ldomain>:
host mail.domain.com [IP Address]:
553 sorry, that domain isn't in my list of allowed rcpthosts; no valid cert for gatewaying (#5.7.1)
I have checked the server to be on a blacklist and it appears not to be on a black list. I have also rebooted the server and verified that DNS is working correctly also ran a virus scan on the system and nothing was found. Any suggestions?