SYMPTOM:
Users stop receiving e-mails via Strategy Narrowcast and Distribution Services 9.x when using Microsoft Outlook 2007 and 2010.
CAUSE:
Microsoft Outlook has moved the e-mail to the junk e-mail location. Microsoft Outlook is treating the e-mail as spam since the sender of the email is not from a actual user.
ACTION:
Click on the section in the Junk email folder to view the file as shown in the image below.

Microsoft Outlook spam / junk email filter should be altered to allow emails from Strategy Distribution Services and Narrowcast to be delivered to the user's mail inbox.