Hi Guys,
Has anybody encountered the same issue. I have one client which not receiving email from us and getting bounced. Interestingly not all emails are bouncing. I have this one mailbox which they are able to received emails and the rest were bouncing regardless if I'm using email domain which the same to the working mailbox.
I can always successfully telnet to their smtp test email however the status is
Queue mail for delivery
451 4.7.0 Timeout waiting for client input
Connection to host lost
I found this article but,the err code is different.
https://supportforums.cisco.com/discussion/11025191/440-other-network-problem-000-errno-60-operation-timed-out
Best regards,