selenium-webdriver – Webdriver异常：“chrome无法访问”

我在ubuntu服务器上运行selenium测试用例,它基本上运行firefox和chrome中的测试用例.
Firefox启动和测试用例成功运行但chrome抛出异常：

*****下面是stacktrace的片段：*****

在端口21549上启动ChromeDriver(v2.8.240825)

PAC支持已禁用,因为没有系统实现

Test IntegrationTest.AdminUserelementscheck失败：

org.openqa.selenium.WebDriverException：chrome无法访问
?(驱动程序信息：chromedriver = 2.8.240825,platform = Linux 2.6.32-431.el6.x86_64 x86_64)(警告：服务器未提供任何堆栈跟踪信息)
[错误]命令持续时间或超时：20.83秒

嗨下面是我的代码的小片段：

public class IntegrationTest {

private static final String configFile="test.properties";

private final String FIREFOX="firefox";

private final String CHROME="chrome";

private final String PHANTOMJS="phantomjs";

private final String BROWSERNAME="browser";

private static Properties props = new Properties();

public WebDriver webDriver;

private static Configuration additionalConfigurations;


@BeforeClass

public static void setUp() throws IOException,SQLException{

props.load(IntegrationTest.class.getResourceAsStream("/" + configFile));
        }

@test

public void AdminUserelementscheck() throws SQLException,IOException {

String[] browsers = props.getProperty(BROWSERNAME).split(",");

System.out.println("Number of browsers specified in conf:"+props.getProperty(BROWSERNAME));

for(String browser:browsers){

System.out.println("Browser currently processing:"+browser);

if(browser.equalsIgnoreCase(FIREFOX))

webDriver = new FirefoxDriver();

else if(browser.equalsIgnoreCase(CHROME))

webDriver = new ChromeDriver();

else

webDriver = new PhantomJSDriver();

running(testServer(3333,fakeApplication()),webDriver,new Callback