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

Network error or timeout in sending or receiving email with Outlook
http://www.desknow.com/kb/idx/4/046/article/

This could be due to many different causes.

  1. Misconfiguration of Outlook. Check your Outlook settings
  2. Network problems. Check that your port 25 (SMTP, for emails that you send) and 110 (POP3, for emails that you receive) are not blocked between your compuer and the computer running DeskNow
  3. Antivirus. This is a very common problem, especially when receiving email through POP3. Many antivirus programs scan POP3 traffic to block viruses. Some cause conflicts with Outlook. Surprisingly, one of the most common to cause problems is Norton Antivirus. See these articles:
    http://support.microsoft.com/default.aspx?scid=kb;en-us;309676
    http://support.microsoft.com/default.aspx?scid=kb;en-us;262086
    http://support.microsoft.com/default.aspx?scid=kb;en-us;310383