We are having Exchange 2013 and all emails are comin & going fine except 1 domain.
From this domain, we can receive the emails but when we send email to them we receive below notification.
Diagnostic information for administrators:<o:p></o:p>
Generating server:FQDN of my mail server
Receiving server: FQDN of far end server (IP address of far end server)
Recipeint email address
Remote Server at FQDN and IP of far end returned '400 4.4.7 Message delayed'
24-08-2016 07:07:58 - Remote Server at FQDN and IP of far end returned
'441 4.4.1 Error encountered while communicating with primary target IP address: "421 4.4.2 Connection dropped due to TimedOut." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed
to all alternate hosts. The last endpoint attempted was IP of far end:25'
All emails to other domains goes well.
Thanks, Rishi Pandit.