I am running Outlook 2011 with a pop/smtp setup.  Sometimes Outlook will just stop receiving emails.  Whenever this happens I log into webmail and I have an email with a very large attachment.  If I delete the email Outlook starts working fine again.  When I had this problem in Outlook for Windows I could just increase the server timeout and it would download the emails.  I am trying to find a similar option in Outlook 2011.