Capture HTTP 401 with Angular.js interceptor

For AngularJS >1.3 use $httpProvider.interceptors.push('myHttpInterceptor');

.service('authInterceptor', function($q) {
    var service = this;

    service.responseError = function(response) {
        if (response.status == 401){
            window.location = "/login";
        }
        return $q.reject(response);
    };
})
.config(['$httpProvider', function($httpProvider) {
    $httpProvider.interceptors.push('authInterceptor');
}])

in app config block:

var interceptor = ['$rootScope', '$q', "Base64", function(scope, $q, Base64) {
  function success(response) {
    return response;
  }

  function error(response) {
    var status = response.status;
    if (status == 401) {
      //AuthFactory.clearUser();
      window.location = "/account/login?redirectUrl=" + Base64.encode(document.URL);
      return;
    }
    // otherwise
    return $q.reject(response);
  }
  return function(promise) {
    return promise.then(success, error);
  }
}];

I don't know why, but response with 401 error goes into success function.

'responseError': function(rejection)
                {
                    // do something on error

                    if (rejection.status == 401)
                    {
                        $rootScope.signOut();
                    }

                    return $q.reject(rejection);
                },
                'response': function (response) {
                    // do something on error
                    if (response.status == 401) {
                        $rootScope.signOut();
                    };
                    return response || $q.when(response);
                }