Making The Change To SMTP Authentication
Entourage - Mac OS X
This guide describes the steps you need to take in order to set up your existing email account to use SMTP authentication in Entourage for Mac OS X, part of the Miscrosoft Office Suite for Mac.
Start up Entourage by clicking it's icon in the dock or by finding the application on your hard drive, navigate to the menu bar at the top of the screen and select "Tools" followed by "Accounts".

A new window appears listing your Internet Email accounts. Select the appropriate email account in the list and click the "Edit" button, or alternatively, double-clicking the email account in the list achieves the same thing.

A new window appears that details the settings for you email account. At the bottom of this window, there is a text field which will contain the name of your Outgoing SMTP Server, underneath this is a button labelled "Click here for advanced sending options". Click this button and tick the checkbox labelled "SMTP Server requires authentication", making sure that the sub-option is set to "Use the same settings as receiving mail server". Close this mini window by clicking the square in the top left corner and click the large OK button to save your changes.

Try sending an email to yourself to test that the outgoing server settings are correct.
If you receive errors make sure that your SMTP server is set to yourdomain.com and remember that these
changes only come into effect after October 12th