Proxy Authentication Required ( Forefront TMG requires authorization to fulfill the request. Access to the Web Proxy filter is denied


#1

hi every one. my application says the below error:
null refrence was not handled by user exception
proxy authentication required.my application has read and write access.
private string GetOAuthUrl()
{ IFluentTwitter twitter;
//Override the callback url if one was entered
if (CallbackUrl != null && CallbackUrl.Trim().Length > 0)
{
twitter = FluentTwitter.CreateRequest().Configuration.UseHttps().Authentication.GetRequestToken(ConsumerKey, ConsumerSecret, CallbackUrl);
}
else
{
twitter = FluentTwitter.CreateRequest().Configuration.UseHttps().Authentication.GetRequestToken(ConsumerKey, ConsumerSecret);
}
var response = twitter.Request();
UnauthorizedToken UnauthorizedToken = response.AsToken();
string AuthorizationUrl = FluentTwitter.CreateRequest().Authentication.GetAuthorizationUrl(UnauthorizedToken.Token);
return AuthorizationUrl;
}
here response .as token() is becoming null and unauthorized url is also becoming null