You need to complete these given prerequisites, you can skip the step if you have already completed.
Sign up for a Mailazy account.
Complete Domain Authentication.
Generate the Mailazy Access Key
Integrate Mailazy with Sendmail
Sendmail requires libsasl in order to properly send authentication requests to Mailazy servers. The saslauthd server daemon is not required unless you plan to receive authentication requests to the same server. For more information on configuring sendmail for SASL support, check the official documentation.
Set the authorization credentials in /etc/mail/access
AuthInfo:smtp.mailazy.com "U:mailazy_apikey" "P:mailazy_yourAPIKey" "M:PLAIN"
Define the Smart Host in /etc/mail/sendmail.mc You should add these lines just after the commented "#dnl define('SMART_HOST', 'smtp.your.provider')dnl" line in the file
define(`RELAY_MAILER_ARGS', `TCP $h 587')dnl
define(`ESMTP_MAILER_ARGS', `TCP $h 587')dnl
Update sendmail.cf and access.db files
(You will need to run these commands as 'su' or 'root')
$ cd /etc/mail
$ m4 sendmail.mc >sendmail.cf
$ makemap hash access.db < access
On older distros, you can run restart sendmail like so:
$ /etc/init.d/sendmail restart
If, however, you're using a newer version, do the following to restart:
$ service sendmail restart