"Login Failure" using LinkedIn OAuth in asp.net mvc 4

I am taking a look at the default OAuth implementation that comes with asp.net mvc 4. It definitely is impressive, as all i had to do was add this line in AuthConfig.cs: ``` OAuthWebSecurity.RegisterLinkedInClient("_key_", "_secret_"); ``` enabling above, did offer up the LinkedIn link to login. I was prompted for password once, but after entering it i got: "Login Failure. Unsuccessful login with service." , and have been getting this ever since w/out ever being prompted for password again. It is not clear to me if this is due to initial bad credentials i entered, or something with the way i set up the key. Also, i don't see the actual controller code anywhere within my app, so even if my login worked, it is not clear how i could obtain information from linked in.. i.e. history. it is nice how easy this integration was, but I am leaning towards a more manual implementation of this? however i can't help but wonder that above implementation probably also works. UPDATE i've traced the problem to be this call: ``` public ActionResult ExternalLogin(string provider, string returnUrl) { return new ExternalLoginResult(provider, Url.Action("ExternalLoginCallback", new { ReturnUrl = returnUrl })); } ``` callback comes back with "401 Unauthorized".. even though the credentials are correct. from what i can gather in other posts, this may be due to incorrectly formed headers by OAuth library?