Gravity form Load By Ajax Cannot Submit - Error 400

I have an issue with Gravity forms. I successfully loaded Gravity Forms via ajax, but I got an error of 400 when I submit the form.

I tried all solutions but still can't submit the forms.

here is my ajax code

var data = {
            action': 'step_3_ajax_content',
            }
$.ajax({
        type: POST,
        url: ajax.url,
        data: data,
        beforeSend: function() {
        $(.loading).show();
        },
            success: function(response) {
                $('.wizards-content-ajax').html(response);
                 $(.loading).hide();
        }
 });

to show forms I use shortcode

?php echo do_shortcode( '[gravityform id=1 title=false description=false ajax=true]' ); ?

I get error /wp-admin/admin-ajax.php#gf_1:1

in my header gravity_form_enqueue_scripts (1, true); // Ajaxed form id = 1