Return Json data to Ajax call

I have a method in MVC that I post to it and I need to return some data back to process. This is my MVC method that I post to and return Value is a json data.

[HttpPost]
public JsonResult GetCalculateAmortizationSchedule()
{
    var data = ...
    var httpClient = new HttpClient();
    var response = httpClient.PostAsJsonAsync("http://localhost:62815/v1/APR/CalculateAmortizationSchedule", data).Result;
    var returnValue = response.Content.ReadAsAsync<Dictionary<int, AmItem>>().Result;
    return Json(returnValue);
}

This is my AJax call that successfully run the MVC method.

$('#MyForm').submit(function (e) {
    debugger;
    $.ajax({
        url: "/home/GetCalculateAmortizationSchedule",
        type: "POST",
        dataType: "json",
        contentType: "application/json; charset=utf-8",                
        success: function (result) {
            alert("success");
        },
        error: function (result) {
            alert("error");
        }
    });
    e.preventDefault();
});

My problem is how to catch the return value from method? when I run this after return Json(returnValue) the value is not returning to Ajax method and instead of seeing the Success Alert I see the error Alert.