We have exchange 2010 server and experiencing mail issue for perticular domain. Mail flow is working fine for other domains.
Scenario- Mails are receiving to our domain sent from perticular domain but the same is getting stuck in queues when we replied or send new mail to perticular domain with below error:
"421 4.4.2 Connection dropped due to ConnectionReset"
And then eventually fail with "#550 4.4.7 QUEUE.Expired; message expired ##"