Microsoft Outlook Express 4,5 & 6

Configuration of both Outlook version are identical.

First select item "Accounts..." from "Tools" menu, like on the picture below.

    

Then a window will appear:

    

Select "Mail" tab, select your mail account and press the "Properties" button. Another window will appear:

    

Select "My server requires authentication" and press the Settings button to configure it further. Another window will appear:

    

Select the "Use same settings as my incoming mail server" radio button.  Press OK, to close the window, press OK on the remaining windows. You have now fully re-configured Outlook Express.