public class Test1 {
    public static WebDriver driver;

    @BeforeTest
    public void setUpDriver() throws IOException, InterruptedException {
      //FirefoxOptions options = new FirefoxOptions();
      //options.setCapability("marionette", false);
      System.setProperty("webdriver.gecko.driver", "C:\Users\****\Downloads\geckodriver-v0.21.0-win64\geckodriver.exe");
      driver = new FirefoxDriver();
      driver.manage().window().maximize();
    }

    @Test(priority=1)
    public void test() throws InterruptedException {
      driver.get("https://google.com");
    }

1532713601535   geckodriver     INFO    geckodriver 0.21.0
1532713601547   geckodriver     INFO    Listening on 127.0.0.1:3012
1532713602248   mozrunner::runner       INFO    Running command: "C:\Program Files\Mozilla Firefox\firefox.exe" "-marionette" "-foreground" "-no-remote" "-profile" "C:\Users\******\AppData\Local\Temp\rust_mozprofile.LUNdmVpn3N1s"
[GFX1]: Potential driver version mismatch ignored due to missing DLLs igd10umd64 v= and igd10iumd64.dll v=0.0.0.0
1532713605654   Marionette      INFO    Listening on port 50526
Jul 27, 2018 1:47:56 PM org.openqa.selenium.remote.ErrorCodes toStatus
INFO: HTTP Status: '404' -> incorrect JSON status mapping for 'unknown error' (500 expected)
Tests run: 2, Failures: 1, Errors: 0, Skipped: 1, Time elapsed: 76.062 sec <<< FAILURE! - in TestSuite
setUpDriver(********.Test1)  Time elapsed: 75.988 sec  <<< FAILURE!
org.openqa.selenium.WebDriverException:
WebDriver:NewSession
Build info: version: '3.13.0', revision: '2f0d292', time: '2018-06-25T15:24:21.231Z'
System info: host: '******-LAPTOP', ip: '*******', os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '1.8.0_171'
Driver info: driver.version: FirefoxDriver
remote stacktrace: WebDriverError@chrome://marionette/content/error.js:211:5
UnknownCommandError@chrome://marionette/content/error.js:455:5
execute/req<@chrome://marionette/content/server.js:503:15
TaskImpl_run@resource://gre/modules/Task.jsm:319:42
TaskImpl@resource://gre/modules/Task.jsm:277:3
asyncFunction@resource://gre/modules/Task.jsm:252:14
Task_spawn@resource://gre/modules/Task.jsm:166:12
execute@chrome://marionette/content/server.js:500:15
onPacket@chrome://marionette/content/server.js:471:7
_onJSONObjectReady/<@chrome://marionette/content/server.js -> resource://devtools/shared/transport/transport.js:483:11
exports.makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/ThreadSafeDevToolsUtils.js:101:14
exports.makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/ThreadSafeDevToolsUtils.js:101:14