使用selenium在火狐浏览器下抓取登录的cookie时，启动后报这样的错误，请大神指教一下：
Exception in thread "main" org.openqa.selenium.remote.UnreachableBrowserException: Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure.
Build info: version: '3.4.0', revision: 'unknown', time: 'unknown'
System info: host: 'USER-20140801HG', ip: '192.168.1.111', os.name: 'Windows 7', os.arch: 'amd64', os.version: '6.1', java.version: '1.8.0_11'
Driver info: driver.version: FirefoxDriver
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:658)
at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:250)
at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:236)
at org.openqa.selenium.remote.RemoteWebDriver.(RemoteWebDriver.java:137)
at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:191)
at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:108)
at org.openqa.selenium.firefox.FirefoxDriver.(FirefoxDriver.java:121)
at ot.TmCookie.getSignCookie(TmCookie.java:19)
at ot.TmCookie.main(TmCookie.java:67)
Caused by: java.lang.NullPointerException
at org.openqa.selenium.remote.service.DriverService.waitUntilAvailable(DriverService.java:192)
at org.openqa.selenium.firefox.XpiDriverService.start(XpiDriverService.java:94)
at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:78)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:637)
... 8 more
你访问的服务器的地址是否正确