How to enable SSL for SMTP in Outlook 2007
Open Outlook 2007 and click on Tools and then Account Settings.
Click on the account you wish to modify and then click on the Change button
Click on More Settings
Select the Advanced tab. Set the Outgoing server (SMTP) port to 465.
Specify SSL at the Use the following type of encrypted connection setting.
Click OK, followed by Next and then Finish.