error 401 cuando solicito get todos los contactos usando GDATA

Estoy usando Gdata y ya con éxito ingresa a Gmail y llamo por debajo del método

- (void)viewController:(GTMOAuth2ViewControllerTouch *)viewController finishedWithAuth:(GTMOAuth2Authentication *)auth{ if (error != nil) { } else{ // i got successful login here self.auth=auth; } } 

En el método anterior obtuve el token Authentifacation y etc. Ahora

 NSString *urlStr = @"https://www.google.com/m8/feeds/contacts/default/full"; NSURL *url = [NSURL URLWithString:urlStr]; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; [self.auth authorizeRequest:request completionHandler:^(NSError *error) { NSString *output = nil; if (error) { output = [error description]; } else { // Synchronous fetches like this are a really bad idea in Cocoa applications // // For a very easy async alternative, we could use GTMHTTPFetcher NSURLResponse *response = nil; NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]; if (data) { // API fetch succeeded output = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease]; } else { // fetch failed output = [error description]; } } }]; 

pero tengo el error 401 por favor me ayuda