hmm.....
IIS restart didn't work.
but I found out that it actially work, if i tpye in the ip addr instead of my computer's full name.
like this:
if i type something like "http://123.456.7.890/BEG/", i can open the page.
if i type something like "http://myComputer/BEG/", i get the 502 bad gateway message.
So now, my problem would be how i can change it back sothat i can use my computer name as the domain??