Selenium Webdriver等待似乎无法正常工作

每当单击“登录”按钮时，就会出现一个覆盖层（灰色半透明屏幕），并且停留几秒钟。因此，Selenium Web驱动程序无法找到元素，因为这种重叠类型将它们隐藏了一段时间，或者至少对我来说是这样。我该如何处理？我发现Thread.sleep这里不是一种有效的方法。

我试过了 -

    public void login(){
        WebDriverWait wait = new WebDriverWait(driver, 60);     

        wait.until(ExpectedConditions.invisibilityOfElementLocated((By.id("ajax-overlay"))));
        wait.until(ExpectedConditions.elementToBeClickable((By.id("okbutton))));
        driver.findElement(By.id("username)).sendKeys("admin");
        driver.findElement(By.id("password")).sendKeys("admin123");
        driver.findElement(By.id("okbutton")).click();   
        wait.until(ExpectedConditions.invisibilityOfElementLocated((By.id("ajax-overlay"))));
}

但似乎没有任何效果，但我仍然出现错误-

org.openqa.selenium.WebDriverException: unknown error: Element <button id="loginDialog:okButton" name="loginDialog:okButton" class="ui-button ui-widget ui-state-default ui-corner-all ui-button-text-only ui-panel-titlebar-icon synchronous" onclick="PrimeFaces.ab({source:'loginDialog:okButton',process:'loginDialog:okButton loginDialog:username loginDialog:password loginDialog:okButton',update:'startingCashFocus loginDialog:dialogFocus loginDialog:lblPassword loginDialog:lblUsername loginDialog:messages',oncomplete:function(xhr,status,args){handleLoginAttempt(xhr, status, args, loginWidget, null); ;}});return false;" tabindex="1" type="submit" role="button" aria-disabled="false">...</button> is not clickable at point (931, 250). Other element would receive the click: <div id="ajax-overlay" class="ui-blockui ui-widget-overlay ui-helper-hidden eternal" style="display: block;"></div>

另外，没有办法找出叠加层ID，谢天谢地，Selenium在错误详细信息中给出了它。