The Connection was refused when attempting to connect with this

I was trying to connect to a website, but was failed using IE.
Then I changed to Netscape, it reminded me such information "The Connection was refused when attempting to connect with this website."
Actually it worked well with the connection of this site before. The only thing I did last night was to "delete cookies" and "delete files" in under Tool's "Internet Options" of IE.
Can anyone help me about how to solve this problem?
Thanks.