IMAP connection problem in Outlook Express

[metinex]

I setup IMAP account in Outlook and Outlook Express. In both application while reading emails, the application hangs for a while.

I got this error message at the end:
Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems and a long period of inactivity.

This IMAP command could not be sent to the server, because the connection is terminated.
Code: 800ccc0f

Any suggestion?