Deferred: Connection timed out with mail.example.com (With Sendmail)

Question

I have configured the sendmail on ubuntu server. Mail are going to all other emails and domains perfectly. But with one domain I am getting the following error, Please suggest:

Nov 8 09:24:24 ABCWEB02 sm-mta[471]: uA894lAY000402: to=, ctladdr= (33/33), delay=00:19:25, xdelay=00:09:06, mailer=esmtp, pri=210473, relay=mail.example.com. [44.44.444.44], dsn=4.0.0, stat=Deferred: Connection timed out with mail.example.com.

Do you get smtp greeting message when you telnet smtp (25) port on mail.XXXXXXXXX.com? [translated: Is it sendmail's fault?] How many hosts are listed in MX record of the domain? How many IPv4&IPv6 addresses do they keep? — AnFi
Don't invent random domain names; example.com exists for precisely this reason. — MSalters

user2557649 user2557649 · Accepted Answer · 2016-11-16T08:44:52

The issue is resolved as following

Check you telnet connection on 25 port (telnet was not getting connected as firewall rules modified for 25 port)

I was using wrong SMTP credentials.

Deferred: Connection timed out with mail.example.com (With Sendmail)

1 Answers