Problem when using 'sign in as a different user'.

Question

I have a standard website (one Web Application and one Site Collection) with some custom pages and webparts.

The issue I'm having is that when I try to switch users, using the "Sign In As a Different User" and entering new credentials (even for another Site Collection admin account), IE tries the account three times, and then it presents a 401 Access Denied screen.

After that, if I erase all the stuff of access denied page from the browser's url, I'm logged as the new account I just had entered and was not accepted.

After researching for a while on google, I found a KB ( http://support.microsoft.com/kb/970814 ) that might relate, but just tested here and it didn't work at all.

The modified method suggested by the KB is the following:

function LoginAsAnother(url, bUseSource) 
{
    document.cookie="loginAsDifferentAttemptCount=0";

    if (bUseSource=="1")
    {
         GoToPage(url);
    }
    else
    {
         //var ch=url.indexOf("?") >=0 ? "&" : "?";
         //url+=ch+"Source="+escapeProperly(window.location.href);
         //STSNavigate(url);
         document.execCommand("ClearAuthenticationCache"); 
    } 
}

But after making this change, it no longer asks for new credentials.

Any ideas?

Answer 1

One of the first things I would do to troubleshoot is to use Fiddler (or other http traffic analyzer) to have a look at the http requests and responses before using the 'Sign in as.." and those after.

It may not give you a direct answer, but by inspecting the headers for each successful request, and comparing with those that are failing with 401 responses, it may give a few clues as to what's going on.