Enable SMTP Authentication for Mac Mail OS X

Enabling SMTP authentication

1. Open MAIL.
2. From the MAIL menu, select Preferences. Select the Accounts icon and click on your email account under the Description heading.  Click on the Edit button on the right.  The Account Information appears. 
3. In the Outgoing Mail Server section, click on the double arrows and select Add Server.. from the menu. The SMTP Server Options box appears.
4. In the Outgoing Mail Server box, enter mail.his.com 
5. In the Authentication box,  click on the double arrows and select Password.
6. In the User Name box, enter your email address.  In the Password box, enter your password for this email address.
7. Click OK to return to the Account information page. In Outgoing Mail Server section, click on the double arrows and select mail.his.com . Note that it will have your email address listed.
8. Change to SMTP port 587 with TLS or SMTP port 465 with SSL
9. The Outgoing Mail Server entry should now show mail.his.com followed by your email address.
10. Click OK to close and then close the Accounts box by clicking the red button.  SMTP authentication has been enabled.