Firefox 47 を使用すると Selenium 2.53.0 で接続エラーが発生するのはなぜですか?

org.openqa.selenium.firefox.NotConnectedException: Unable to connect
to host 127.0.0.1 on port 7055 after 45000 ms.

System.setProperty("webdriver.gecko.driver", "/path/to/geckodriver");

<dependency>
    <groupId>io.github.bonigarcia</groupId>
    <artifactId>webdrivermanager</artifactId>
    <version>5.1.0</version>
</dependency>

WebDriverManager.firefoxdriver().setup();

public class FirefoxTest {

    protected WebDriver driver;

    @BeforeClass
    public static void setupClass() {
        WebDriverManager.firefoxdriver().setup();
    }

    @Before
    public void setupTest() {
        driver = new FirefoxDriver();
    }

    @After
    public void teardown() {
        if (driver != null) {
            driver.quit();
        }
    }

    @Test
    public void test() {
        // Test code goes here
    }
}