OS X SMTP issue - Unable to send email (gmail)
To make new SMTP:

Open Mail Preferences.

Click on Accounts.

If you have more than one click on one of them.

In that window look for Outgoing Mail server (SMTP).

from the pick up select Edit SMTP server.



In the new window select the (+) and enter a description (name you like), and smtp.gmail.com



Back in Account screen select that name.