Full calender drag event not working event date after one week days - fullcalendar-scheduler

Question

I have trying to implement auto scheduling employee in each days. I have tried to drag on employee on other day.
But i have face the issue on employee dragging not working current day after one week days.
Any ideas about my code, which place i have wrong.
full_calender = $('#calendar').fullCalendar({
header: {
left: 'prev,next today',
center: 'title',
right: 'month,listWeek,listDay'
},
views: {
listDay: { buttonText: 'List View' },
listWeek: { buttonText: 'Week View' },
month: { buttonText: 'Month View' },
},
defaultDate: default_date,
editable: true,
selectable: true,
selectHelper: true,
eventLimit: true, // allow "more" link when too many events
eventResourceEditable: true,
/*select: function (start, end) {
addSelectedEvent(start, end);
},*/
eventConstraint: {
start: moment().format('YYYY-MM-DD HH:mm'),
end: '2100-01-01' // hard coded goodness unfortunately
},
dragRevertDuration: 1000,
eventDrop: function(event, delta,revertFunc) {
//if (!confirm('Are you sure '+ event.title + ' Moved On '+event.start.format())) {
//updateDroppableEvent(event.id,event.start.format());
var data = {
'action_update_droppable_event' : 'yes',
'event_id' : event.id,
'move_date' : event.start.format(),
};
$.ajax({
URL : '',
method : 'POST',
data : data,
dataType: 'json',
success : function(res){
if(res.status == 'success'){
$('#calendar').fullCalendar( 'renderEvent', event );
}else{
alert(res.msg);
revertFunc();
//window.location.reload();
}
},
error : function(res){
//console.log(res);
}
});
},
eventSources: [
{
url: base_url + 'admin_dashboard/render_current_events',
//url: base_url + 'admin_dashboard/get_holiday_list',
type: 'POST',
data: {
zone_id: '<?php echo $_REQUEST['zone_id'] ?>',
custom_param2: 'somethingelse'
},
error: function () {
alert('there was an error while fetching events!');
}
}
],
/* Delete Event */
eventClick: function (calEvent, jsEvent, view) {
deleteSelectedEvent(calEvent);
},
eventAfterAllRender: function (view) {
//$(".fc-event-container a").append("<span class='event_edit_popup'><i class='icon-eye-open'></i></span>");
// events: base_url + 'admin_dashboard/get_holiday_list',
}
});