When i am trying to run this code in .net framework i get status code 500 but i don’t know why?
back end

public ActionResult getvisit(int id)
        {
            var query = __db.Visits.Where(v => v.fkDoctor == id && v.fkPatient == null).Select(v => new {v.Id, v.sDate}).ToList() ;
            List<object> visits = new List<object>();
            foreach (var item in query)
            {
                var sdatetime = new PersianDateTime(item.sDate);
                visits.Add(new {item.Id, sdatetime.Date, sdatetime.TimeOfDay});
            }
            var result = Json(visits, JsonRequestBehavior.AllowGet);
            return result;
        }

front end

docSpan.on("change", function () {
        const id = docSpan.val();
        visitSpan.empty();
        visitSpan.append(
            "<option value=''>انتخاب کنید</option>"
        )
        $.post("/Home/getvisit", { id: id })
            .done(function (res) {
                console.log(res);
                for (let item of res) {
                    console.log(item);
                    visitSpan.append(
                        `<option value=${item.id}>${item.sdate} || ${item.stime}</option>`
                    );
                }
            })
            .fail(function () {

            })
            .always(function () {

            });
    })

I don’t have any idea why this happen.