404 undefined Error while calling $http post request

1

i am calling my $http post method from multiple controller but getting 404 undefined error response from server.

Getting error when multiple post request coming together otherwise its working fine.
is there any solution to lock for dead lock condition in angular.
My Code

    var config = {
        'headers': { 'Authorization': mytoken }
    };
    var deferred = $q.defer();
    $http.post(url, data, config)
    .success(function (data, status) {
        deferred.resolve(data);
    })
    .error(function (data, status) {
       ///here i am getting 404 undefined
      alert(data +"status : "+ status);
    });