-To set your SMTP server, login to the WHMCS Admin Area, then click on Addons->ServerPing
-Make sure your Alert From Email Address is set correctly to an email address supported by your SMTP server.
-Enter in your SMTP Host, Username, password, port, and SSL type and save the changes.
-If you have a firewall installed on your check worker server, make sure that the outgoing port you specified above is open on in the firewall on all of your check worker servers.
ServerPing will now start sending email alerts via the entered SMTP server.
To switch back to sendmail, remove the SMTP Host, Username, password, port and ServerPing will automatically switch back to using sendmail.
