OpenQA.Selenium.NoSuchElementException:使用Selenium和C#在页面上定位元素时无法定位元素错误

我正在尝试在编辑了站点

它具有css选择器:

#autocplt_wrap > ul:nth-child(1) > li:nth-child(1) > span:nth-child(1) > a:nth-child(1)

和x-Path:

/html/body/div[2]/div[1]/div[3]/div[2]/div[1]/div/div[1]/div[2]/div/div/ul[1]/li/span/a[1]

我的代码是:

IWebDriver driver = new FirefoxDriver();
WebDriverWait wait = new WebDriverWait(driver, TimeSpan.FromSeconds(10));
//load webdriver
driver.Manage();
driver.Navigate().GoToUrl("https://dict.naver.com/linedict/zhendict/#/cnen/home");
driver.FindElement(By.ClassName("ac_input")).SendKeys("睡觉" + Keys.Enter);
driver.FindElement(By.CssSelector("#autocplt_wrap > ul:nth-child(1) > li:nth-child(1) > span:nth-child(1) > a:nth-child(1)"));

无论我尝试什么，我总是会收到错误消息:

No matter what I try I always get the error:

Unhandled exception. OpenQA.Selenium.NoSuchElementException: Unable to locate element: #autocplt_wrap > ul:nth-child(1) > 
li:nth-child(1) > span:nth-child(1) > a:nth-child(1)
   at OpenQA.Selenium.Remote.RemoteWebDriver.UnpackAndThrowOnError(Response errorResponse)
   at OpenQA.Selenium.Remote.RemoteWebDriver.Execute(String driverCommandToExecute, Dictionary`2 parameters)
   at OpenQA.Selenium.Remote.RemoteWebDriver.FindElement(String mechanism, String value)
   at OpenQA.Selenium.By.<>c__DisplayClass29_0.<CssSelector>b__0(ISearchContext context)
   at OpenQA.Selenium.By.FindElement(ISearchContext context)
   at OpenQA.Selenium.Remote.RemoteWebDriver.FindElement(By by)