Why i am unable to receive the data sent through ajax call(post request) ?

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C#

Ajax

jQuery

I am trying to insert data through POSTRequest in clientside code(jquery ajax call).
When the request goes to controller methods i am not able to retrieve the data sent.When it hits the web api controlller data is null.

What I have tried:

Clientside code:

function AddUser()
        {         
            var user = { UserID: $("#UidTxt").val, UserName: $("#UnameTxt").val, Password: $("#PwdTxt").val, Email: $("#EmailTxt").val, Address: $("#AddrTxt").val, DOB: $("#DobTxt").val, Phone: $("#PhoneTxt") };
            $.ajax({
                url: 'http://localhost:61540/api/UserDetails/AddUser',
                type: POST,
                data: JSON.stringify(user),
                dataType: "json",
                contentType: "application/json;charset=utf-8",
                success: function (data) {
                    alert("success! data is posted/inserted.")
                },
                error: function (xhr, status) {
                    alert(xhr.ResponseText);
                }
            });
        }

Web Api Controller Methods:

[System.Web.Http.AcceptVerbs("POST")]
[ActionName("AddUser")]
[System.Web.Http.HttpPost]
[System.Web.Http.HttpOptions]
public List<UserDetails> AddUser(UserDetail oUserList)
{
    if (oUserList != null)
    {
    db.UserDetails.Add(oUserList);
    db.SaveChanges();
    }
    var userList = db.UserDetails.ToList();
    return DTOConverter.ConvertUserDetail(userList);
}

While Debugging,the call hits the controller methods and i find oUserList object is null.
Am i passing the data correctly? correct me if am wrong.
Thanks in advance .