Check the following:
in /etc/mail/sendmail.cf do a search for DS and see what it says.
grep DS /etc/mail/sendmail.cf
If it states DS only, it uses local / so a SMTP gateway is not configured. Additionally, it may state GW address, which needs to be changed (if it is an older entry).
Example of what is displayed:
COMPONENT_NAME: CMDSEND sendmail.cf
DSmailer:relayhostname
DSserver01.aliant.net
Once you make the change, you have to force sendmail to re-read the configuration file as below.
kill -15 `head -1 /etc/mail/sendmail.pid`
If the process srcmstr is running, check with ps -ef | grep srcmstr you will also have to run the following command:
refresh -s sendmail
To restart the Sendmail process, issue the following command on the command line.
startsrc -s sendmail -a “-bd -q30m”
Finally clear the error report with “errclear 0”