From: DeskNow Knowledge Base
http://www.desknow.com/kb/

I get a timeout when trying to download email with POP3 from Outlook. The message quotes 'Error Number: 0x800CCC0F'
http://www.desknow.com/kb/idx/4/053/article/

The full text of the message is typically something like:

Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity.

etc.

The most common cause of this problem is the mail filtering function of Symantec/Norton Antivirus. Other antivirus / firewall software can cause this conflict with Outlook. This is not related to DeskNow. Check this article for more details:

http://support.microsoft.com/?kbid=813514

Solution:

use DeskNow antivirus scanning (in conjunction with your antivirus) to scan for mail viruses, and disable inbound email scanning (not file scanning) in Norton AV.