I upgraded our server from 5.0.9 GA to 5.0.10 and now we are no longer able to receive inbound email. The sender always receives the following message:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 554 554 5.7.1 Service unavailable; Client host [18.104.22.168] blocked using relays.ordb.org; ordb.org was shut down on December 18, 2006. Please remove from your mailserver. (state 14).
What has changed?