Question : HTTP Error 400 Bad request

Hi,
When a user of our Intranet tries to connect to the home page, he gets the  HTTP Error 400: Bad request.

It's not a problem of his PC, because I tried to login with my account and it worked fine. So I guess it's a problem of his profile... but I don't think it's a IIS setting. I have no idea what's wrong with it and what I should check to make it work with his account.

Any idea?
Thank you in advance

Answer : HTTP Error 400 Bad request

how are you trying to authenticate? Through the builtin windows authetication in IIS directory propeties page?