Jquery-chosen is not working on ajax appended select

I am facing a strange problem regarding Jquery-Chosen. I have a multi select box inside a pop-up whose options are populated using ajax call. Unfortunately Jquery-Chosen is not working on it. But if I use a static multi select box in the same place, it works fine. I have googled a lot but can not find a solution.

Following is my HTML code -

<select multiple class="tid form-control assign_teacher_dropdown" name="assign_teacher[]">
</select>

Following is my Jquery code -

$.ajax({
    url: '/getclass/'+id,
    type: 'get',
    dataType: 'json',
    success: function (response) {
        if(response.status == '200') { 
            var class_info = response.class;                   
            var teacher_info = class_info.teacher;
            $('.assign_teacher_dropdown').empty();
            $('.ttterm_dropdown').empty();
            if(!teacher_info){
                $('.assign_teacher_dropdown').append('<option value="">Please select one</option>');
            }
            $('.class-id').val(class_info.id);
            $('.class-name').val(class_info.class_name);
            $('.class-code').val(class_info.class_code);
            $('.start-date').val(class_info.start_date);
            $('.end-date').val(class_info.end_date);
            var teacherDropdown = '';
            $.each(response.teachers, function( index, value ) {
                var optionSelected = '';
                if(teacher_info) {
                    if(response.selected_teacher.indexOf(index) !=-1){
                        var optionSelected = 'selected';                            
                    }
                }
                teacherDropdown = '<option '+optionSelected+' value="'+index+'">'+value+'</option>';
                $('.assign_teacher_dropdown').append(teacherDropdown);

            });

            $.each(response.terms, function( index, term ) {
                var optSelected = '';
                if(term) {
                    if(index == class_info.term_id){
                        var optSelected = 'selected';
                    }
                }
                var termDropdown = '<option '+optSelected+' value="'+index+'">'+term+'</option>';
                $('.tterm_dropdown').append(termDropdown);
            });

            $('.chosen-container-single-nosearch').hide();
            $('.assign_teacher_dropdown').show();
            $('.tterm_dropdown').show();
            $('#class-update-modal-update').modal('show');
        }
        else {
            validation.html(getMessage(response.message, 'danger'));
        }
        window.scrollTo(0, 0);
        $(".chosen-select").chosen(); ////for static multi select which is working fine
        $('.assign_teacher_dropdown').chosen(); ////it is not working
    }
});

The response -

response.teachers = Object { 2ee71930-70f9-11e7-8040-0744cf2f827d: "Raihan2 Razi2", 47e2f900-6c7d-11e7-98d2-ebfd03a47749: "Teacher -1", 5873df40-7028-11e7-a3a6-4b6f2ca6ed6b: "Teacher Akter", 0ad51850-7107-11e7-a380-8b0b33c8ce62: "Rakib-3 Hasan-3", 63cd0d30-7105-11e7-b09d-a7232d9caeba: "Rakib-2 Hasan-2", 6c2ab790-70f7-11e7-a4f5-aba1de53d767: "Raihan1 Razi1", a6a47520-70f3-11e7-85e1-d760ee2c8a38: "Raihan Razi", 331ba070-7114-11e7-bdd1-2107af6559b4: "Rakib-4 Hasan-4", cbf1d490-7028-11e7-bab1-97745facf387: "Teacher Mizan" }
teacher_info = {id: "5873df40-7028-11e7-a3a6-4b6f2ca6ed6b", email: "akter@wearedando.com", first_name: "Teacher", last_name: "Akter", dob: null, …}

The output -

N.B.: The multi select is located inside a modal.

N.B.: Static multi select works fine in the same position.

Any help is highly appreciated. Thanks in advance.

So far what I have tried -

1. Taken all the options in a variable and used .html() rather than appending
2. Tried assigning a dynamic class along with .assign_teacher_dropdown and called .chosen() on that dynamic class.
3. Separated the .chosen() from the ajax call and called it using a separate function.