使用Chrome浏览器在Selenium中下拉选择问题

Question

我正在尝试从Chrome浏览器的下拉列表中选择值，但它总是给我错误：

Exception in thread "main" org.openqa.selenium.NoSuchElementException: no such element: Unable to locate element: {"method":"id","selector":"select2-ddlConcern-result-dvsy-23"}
  (Session info: chrome=64.0.3282.186)

以下是我的代码。问题在最后一行。任何人都可以帮助我吗？

    public static void main(String[] args) throws InterruptedException {

    System.setProperty("webdriver.chrome.driver", "D:\\eclipse\\ChromeDriver\\chromedriver.exe");
    WebDriver driver = new ChromeDriver();
    driver.get("http://192.165.0.12/knowmax4_idea_new");
    driver.manage().window().maximize();

    WebElement email = driver.findElement(By.id("txtLoginId"));
    email.sendKeys("xxx");

    WebElement password = driver.findElement(By.id("txtPassword"));
    password.sendKeys("xxxxxxx");

    WebElement submit = driver.findElement(By.id("btnLogin"));
    submit.click();
    Thread.sleep(12000);

    WebElement MobileNumber = driver.findElement(By.id("txtMobileNo"));
    MobileNumber.sendKeys("9855958911");

    WebElement customer = driver.findElement(By.xpath("//*/div[2]/div[1]/div[1]/div[2]/div[2]/div[2]/input"));
    customer.sendKeys("Manpreet Singh");

    WebElement issue = driver.findElement(By.xpath("//*/div[2]/div[1]/div[1]/div[2]/div[2]/div[3]/span/span[1]/span/span[2]"));
    issue.click();

    //WebElement issue = driver.findElement(By.id(""));

    //Select dropdown = new Select(driver.findElement(By.className("select2-selection__arrow")));
    //((WebElement) dropdown).click();

    WebElement iselection = driver.findElement(By.id("select2-ddlConcern-result-dvsy-23"));
    iselection.click();