Outlook 2003 Failed to update headers

[Danaloha]

I have been using outlook for about a year. After receiving several emails
today Outlook stopped completing it's updates and forwarding my emails from
my aol account.
Any ideas why I now get the message

The TCP/IP connection was unexpectedly terminated by the server.
Protocol: IMAP
Server: imap.aol.com
Port: 143

Thanks