Unable to locate element using ID or Name - selenium-webdriver

Question

HTML:
<input name="txtAnswer" type="text" maxlength="20" id="txtAnswer" class="box1">
Code trials:
driver.findElement(By.xpath("//table[#id='tblSecurityAnswer']//tbody//tr[2]//td[2]//input[#id='txtAnswer']")).sendKeys("green");
and also:
driver.findElement(By.cssSelector("//tr:nth-child(1) > td > table > tbody >
// tr:nth-child(2) > td:nth-child(2)"));
public static void main(String[] args) throws InterruptedException {
WebDriver driver;
// IE webdriver
// System.setProperty("webdriver.ie.driver", "C:\\IEDriverServer.exe");
// driver = new InternetExplorerDriver();
System.setProperty("webdriver.chrome.driver", "C:\\chromedriver.exe");
driver = new ChromeDriver();
// Maximize the browser window
driver.manage().window().maximize();
// navigate to specified url
driver.get("http://dxbqcapp01/molforms/login.aspx");
driver.findElement(By.id("txtUserName")).sendKeys("MS200963915");
driver.findElement(By.id("txtPassword")).sendKeys("test#123");
driver.findElement(By.xpath("//input[#type='submit' and #value='Submit']")).sendKeys(Keys.ENTER);
driver.findElement(By.id("txtAnswer")).sendKeys("green");

Answer 1

The error stack trace would have helped us to debug your issue in a better way. However to send a character sequence to the desired element you have to induce WebDriverWait for the element to be clickable and you can use either of the following Locator Strategies:
cssSelector:
new WebDriverWait(driver, 20).until(ExpectedConditions.elementToBeClickable(By.cssSelector("input.box1#txtAnswer"))).sendKeys("green");
xpath:
new WebDriverWait(driver, 20).until(ExpectedConditions.elementToBeClickable(By.xpath("//input[#class='box1' and #id='txtAnswer']"))).sendKeys("green");