Jquery ajax is sending null value to database in MVC

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    <div class="form-group">
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        <br>
        
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    </div>

$(document).ready(function () {
            $("#insertForm").validate({
                rules: {
                    'textt': {
                        required: true,
                        minlength: 5,
                        maxlength: 8

                    },
                    'text1': {
                        required: true,
                        minlength: 5,
                        maxlength: 8
                    },
                    'text2': {
                        required: true,
                        email: true
                    },
                    'text3': {
                        required: true,
                        minlength: 5,
                        maxlength: 8
                    }

                },
                messages: {
                    'textt': {
                        required: "Enter the Name",
                        minlength: "Minimum Length 5",
                        maxlength: "Maximum Length 8"

                    },
                    'text1': {
                        required: "Enter Username",
                        minlength: "Minimum Length 5",
                        maxlength: "Maximum Length 8"
                    },
                    'text2': {
                        required: "Valid Email Required",
                        email: "Please Enter valid email abc@gmail.com"
                    },
                    'text3': {
                        required: "Passoword is required",
                        minlength: "Minimum Length of Password 5",
                        maxlength: "Maximum Length of Password 8"
                    }
                },
                submitHandler: function (form) {
                    form.submit();
                }
            });

            $("#btn1").click(function () {
                var isvalid = $("#insertForm").valid();

                if (isvalid) {
               
                    Employee_Ajax();

                }
                else {
                    bootbox.alert("Data is not entered");
                }


            });


            function Employee_Ajax() {
                var employee ={
                    textt: $("txt1").val(),
                    text1: $("txt2").val(),
                    text2: $("txt3").val(),
                    text3: $("txt4").val()
                }
                $.ajax({
                  
                    url: "@Url.Action("EmployeesData", "Home")",
                    data: JSON.stringify("employees", employee),
                    type: "POST",
                    contentType: "application/json;charset=utf-8",
                    dataType: "JSON",
                    success: function (data) {
                        if (data != "") {
                            bootbox.alert("Data Saved Successfully!!!!");
                            
                        }
                        else {
                            bootbox.alert("data not saved! ERROR");
                        }
                    },

                    error: function (fail) {
                        console.log(fail);
                    }

                });


            }
        });