In the e-mail account defined in Outlook, under advanced settings, up
the timeout value.

Disable e-mail scanning in your anti-virus program.  If it doesn't let
you disable e-mail scanning then uninstall the product and then
reinstall but select to perform a custom install and do NOT include
e-mail scanning.  Scanning e-mail duplicates the detection of the
on-access scanner.

For future reference, when posting a problem please include your version of
Outlook, email account type, and any troubleshooting you've done yourself at
the very least. Makes for less guesswork when trying to duplicate the problem
and determine a solution.