In my Queue Viewer, I see the following error next to a queue called "hub version 14":
451 4.4.0 Primary target IP address responded with: “451 5.7.3 Cannot achieve Exchange Server authentication.” Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.
My two servers are
Mail 1 and Mail2
If I am on Mail 1 and I do "Telnet localhost 25" then ehlo, I get a set of SMTP verbs.
If I am on Mail 1 and I do a "Telnet Mail 2 25" then ehlo, I get a set of SMTP verbs but not all of the ones I got when I tried the localhost telnet.
Please see screen shots for two different lists.
Is this normal or does this show that my firewall is blocking some traffic and causing my initial errror above?