来自MVC Controller的JSONResult返回HTTP 403错误

Question

我正在从mvc视图到控制器执行post函数，该控制器工作正常并将数据插入数据库但是当我尝试将jsonresult从控制器返回到视图时，它返回一个http 403禁止错误。我也尝试直接访问该特定操作，它返回相同的403禁止错误。我有什么想法吗？

控制器

 <HttpPost()> _
    Function Create(ByVal collection As ExternalMail) As JsonResult
        Try
            If ModelState.IsValid Then
                _repositoryForExternalMail.Save(collection, "")
            End If

            Return Json(New ExternalMail With {.CostCentreCode = collection.CostCentreCode, .Day = collection.Day, .Quantity = collection.Quantity, .ExternalMailItemID = collection.ExternalMailItemID, .ExternalMailLocationID = collection.ExternalMailLocationID}, JsonRequestBehavior.AllowGet)

        Catch
            Return Json("An Error Occurred")
        End Try
    End Function

JSON

$(document).ready(function () {

    var exturl = '@Url.Action("Create", "ExternalMail")';
    $("#ExtMailCreate").click(function () {


        var dataJSON = JSON.stringify(SaveExternalMail());

                    $.ajax({
                        type: "POST",
                        url: exturl,
                        data: dataJSON,
                        contentType: 'application/json; charset=utf-8',
                        success: function (data) {
                            showMessage("test", "information");
                        },
                        error: function (xhr, textStatus, errorThrown) {
                            $("#result").append(xhr.responseText);
                            $("#result").append(textStatus);
                            $("#result").append(errorThrown);
                        }


                    });

    });

});