I am having an issue with some domains rejecting connections from one of our Exchange 2007 servers. The error I get is below.
451 4.4.0 Primary target IP address responded with: "554 You are not allowed to connect.." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.
Most emails go out without any issues. I find this error has been coming up when emailing large companys like banks.
Our reverse dns is setup correctly and we are not on any blacklists.
It is the "554 You are not allowed to connect.." that is throwing me off. Using a smarthost will deliver the emails, but it is not the prefered method of delivery.