Hello Team,

I have configured the relay on the serverAIX7.3 but the email not received on target emails. also we have added relay servers entry in the /etc/hosts files and restarted the sendmail service but seem the error came. 

bash-5.2# cat /etc/mail/sendmail.cf |grep -i DS
# @(#)24        1.78  src/bos/usr/sbin/sendmail/sendmail.cf, cmdsend, bos720 6/6/12 04:39:10
# @(#)21        1.3  src/bos/usr/sbin/sendmail/cf/cf/sendmail.cf, cmdsend, bos73B, b2022_21A3 4/28/22 08:51:06
# COMPONENT_NAME: CMDSEND sendmail.cf
DSsmtp-out.dnaip.fi

when we checked the files under the path /var/spool/mqueue which generated after sending email from the server. wondering that after some time, we observed that same files we can see error like MDeferred: Connection timed out with mx.dnaip.fi

bash-5.2# oslevel -s
7300-03-01-2520
bash-5.2#

could you please help us what needs to check to correct this one.

Two ideas:
Make sure the smarthost is accessible from the host - debug smtp with telnet 
The server should not care about the MX record if it is correctly in sendmail smarthost mode so something is wrong there.