Exchange error sending mail
Posted on 2011-05-04
I'm using Exchange 2010 Queue Viewer tool and sometimes appear mails that cannot be delivered with error "451 4.4.0 Primary target IP address responded with: 421 4.2.1 Unable to connect. Attempted failover to alternate host, but that did not succeed. Either there are no alternate host, or delivery failed to all alternate host"
The recipient email address is correct and the server is working ok with other recipients.