Export to Excel not working on iis server

protected void btn_export_to_excel_Click(object sender, EventArgs e)
{
    Export_To_Excel();
}

public void Export_To_Excel()
{
    Excel.Application xlApp = new Excel.Application();
    object misValue = System.Reflection.Missing.Value;
    Excel.Workbook xlWorkBook = xlApp.Workbooks.Add(misValue);
    Excel.Worksheet xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
    char x = 'A';

    for (int i = 4; i < grd_employee.Columns.Count - 6; i++)
    {
        xlWorkSheet.Cells[1, i - 3] = grd_employee.Columns[i].ToString();
        xlWorkSheet.Range[x + "1"].Font.Bold = true;
        xlWorkSheet.Range[x + "1"].Borders.Color = Color.Black;
        x++;
    }

    int j = 2;
    for (int i = 0; i < grd_employee.Rows.Count; i++)
    {
        x = 'A';
        #region start
        Label lbl_emp_type_Name = (Label)grd_employee.Rows[i].FindControl("lbl_emp_type_Name");
        xlWorkSheet.Cells[j, 1] = lbl_emp_type_Name.Text;
        Label lbl_designation_Name = (Label)grd_employee.Rows[i].FindControl("lbl_designation_Name");
        xlWorkSheet.Cells[j, 2] = lbl_designation_Name.Text;
        Label lbl_company_name = (Label)grd_employee.Rows[i].FindControl("lbl_company_name");
        xlWorkSheet.Cells[j, 3] = lbl_company_name.Text;
        Label lbl_employee_name = (Label)grd_employee.Rows[i].FindControl("lbl_employee_name");
        xlWorkSheet.Cells[j, 4] = lbl_employee_name.Text;
        Label lbl_emp_name_thai = (Label)grd_employee.Rows[i].FindControl("lbl_emp_name_thai");
        xlWorkSheet.Cells[j, 5] = lbl_emp_name_thai.Text;
        Label lbl_emp_last_name = (Label)grd_employee.Rows[i].FindControl("lbl_emp_last_name");
        xlWorkSheet.Cells[j, 6] = lbl_emp_last_name.Text;
        Label lbl_last_name_thai = (Label)grd_employee.Rows[i].FindControl("lbl_last_name_thai");
        xlWorkSheet.Cells[j, 7] = lbl_last_name_thai.Text;
        Label lbl_nick_name = (Label)grd_employee.Rows[i].FindControl("lbl_nick_name");
        xlWorkSheet.Cells[j, 8] = lbl_nick_name.Text;
        Label lbl_permenent_address = (Label)grd_employee.Rows[i].FindControl("lbl_permenent_address");
        xlWorkSheet.Cells[j, 9] = lbl_permenent_address.Text;
        Label lbl_Present_address = (Label)grd_employee.Rows[i].FindControl("lbl_Present_address");
        xlWorkSheet.Cells[j, 10] = lbl_Present_address.Text;
        Label lbl_mobile_no = (Label)grd_employee.Rows[i].FindControl("lbl_mobile_no");
        xlWorkSheet.Cells[j, 11] = lbl_mobile_no.Text;
        Label lbl_telephone_no = (Label)grd_employee.Rows[i].FindControl("lbl_telephone_no");
        xlWorkSheet.Cells[j, 12] = lbl_telephone_no.Text;
        Label lbl_student_date = (Label)grd_employee.Rows[i].FindControl("lbl_student_date");
        xlWorkSheet.Cells[j, 13] = lbl_student_date.Text;
        Label lbl_employement_date = (Label)grd_employee.Rows[i].FindControl("lbl_employement_date");
        xlWorkSheet.Cells[j, 14] = lbl_employement_date.Text;
        Label lbl_date_of_birth = (Label)grd_employee.Rows[i].FindControl("lbl_date_of_birth");
        xlWorkSheet.Cells[j, 15] = lbl_date_of_birth.Text;
        Label lbl_place_of_birth = (Label)grd_employee.Rows[i].FindControl("lbl_place_of_birth");
        xlWorkSheet.Cells[j, 16] = lbl_place_of_birth.Text;
        Label lbl_nationality = (Label)grd_employee.Rows[i].FindControl("lbl_nationality");
        xlWorkSheet.Cells[j, 17] = lbl_nationality.Text;
        Label lbl_religion = (Label)grd_employee.Rows[i].FindControl("lbl_religion");
        xlWorkSheet.Cells[j, 18] = lbl_religion.Text;
        Label lbl_education = (Label)grd_employee.Rows[i].FindControl("lbl_education");
        xlWorkSheet.Cells[j, 19] = lbl_education.Text;
        Label lbl_marital_status = (Label)grd_employee.Rows[i].FindControl("lbl_marital_status");
        xlWorkSheet.Cells[j, 20] = lbl_marital_status.Text;
        Label lbl_id_card_no = (Label)grd_employee.Rows[i].FindControl("lbl_id_card_no");
        xlWorkSheet.Cells[j, 21] = lbl_id_card_no.Text;
        Label lbl_ss_card_no = (Label)grd_employee.Rows[i].FindControl("lbl_ss_card_no");
        xlWorkSheet.Cells[j, 22] = lbl_ss_card_no.Text;
        Label lbl_tax_card_no = (Label)grd_employee.Rows[i].FindControl("lbl_tax_card_no");
        xlWorkSheet.Cells[j, 23] = lbl_tax_card_no.Text;
        Label lbl_barcode_no = (Label)grd_employee.Rows[i].FindControl("lbl_barcode_no");
        xlWorkSheet.Cells[j, 24] = lbl_barcode_no.Text;
        Label lbl_resignd_date = (Label)grd_employee.Rows[i].FindControl("lbl_resignd_date");
        xlWorkSheet.Cells[j, 25] = lbl_resignd_date.Text;
        Label lbl_remarks = (Label)grd_employee.Rows[i].FindControl("lbl_remarks");
        xlWorkSheet.Cells[j, 26] = lbl_remarks.Text;

        x = 'A';
        for (int col = 1; col <= 26; col++)
        {
            string range = x.ToString() + j.ToString();
            xlWorkSheet.Range[range].Font.Color = grd_employee.Rows[i].ForeColor;
            xlWorkSheet.Range[range].Borders.Color = Color.Black;
            xlWorkSheet.Range[range].Font.Bold = true;
            x++;
        }
        j++;
        xlWorkSheet.Columns.AutoFit();
        #endregion
    }
    xlWorkSheet.Columns.AutoFit();
    xlApp.Visible = true;

    releaseObject(xlWorkSheet);
    releaseObject(xlWorkBook);
    releaseObject(xlApp);

}

private void releaseObject(object obj)
{
    try
    {
        System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
        obj = null;
    }
    catch (Exception)
    {
        obj = null;

    }
    finally
    {
        GC.Collect();
    }
}