java.lang.NullPointerException

gistfile1.txt

java.lang.NullPointerException
	at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:152)
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:636)
	at io.appium.java_client.DefaultGenericMobileDriver.execute(DefaultGenericMobileDriver.java:40)
	at io.appium.java_client.AppiumDriver.execute(AppiumDriver.java:1)
	at io.appium.java_client.android.AndroidDriver.execute(AndroidDriver.java:1)
	at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:369)
	at io.appium.java_client.DefaultGenericMobileDriver.findElement(DefaultGenericMobileDriver.java:56)
	at io.appium.java_client.AppiumDriver.findElement(AppiumDriver.java:1)
	at io.appium.java_client.android.AndroidDriver.findElement(AndroidDriver.java:1)
	at org.openqa.selenium.remote.RemoteWebDriver.findElementByXPath(RemoteWebDriver.java:474)
	at io.appium.java_client.DefaultGenericMobileDriver.findElementByXPath(DefaultGenericMobileDriver.java:134)
	at io.appium.java_client.AppiumDriver.findElementByXPath(AppiumDriver.java:1)
	at io.appium.java_client.android.AndroidDriver.findElementByXPath(AndroidDriver.java:1)
	at org.openqa.selenium.By$ByXPath.findElement(By.java:361)
	at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:361)
	at io.appium.java_client.DefaultGenericMobileDriver.findElement(DefaultGenericMobileDriver.java:52)
	at io.appium.java_client.AppiumDriver.findElement(AppiumDriver.java:1)
	at io.appium.java_client.android.AndroidDriver.findElement(AndroidDriver.java:1)
	at org.openqa.selenium.support.ui.ExpectedConditions.findElement(ExpectedConditions.java:895)
	at org.openqa.selenium.support.ui.ExpectedConditions.access$000(ExpectedConditions.java:41)
	at org.openqa.selenium.support.ui.ExpectedConditions$6.apply(ExpectedConditions.java:181)
	at org.openqa.selenium.support.ui.ExpectedConditions$6.apply(ExpectedConditions.java:178)
	at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:238)
	at appium.Riot.loginTest(Riot.java:97)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:100)
	at org.testng.internal.Invoker.invokeMethod(Invoker.java:646)
	at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:811)
	at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1137)
	at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:129)
	at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:112)
	at org.testng.TestRunner.privateRun(TestRunner.java:753)
	at org.testng.TestRunner.run(TestRunner.java:607)
	at org.testng.SuiteRunner.runTest(SuiteRunner.java:368)
	at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:363)
	at org.testng.SuiteRunner.privateRun(SuiteRunner.java:321)
	at org.testng.SuiteRunner.run(SuiteRunner.java:270)
	at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
	at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
	at org.testng.TestNG.runSuitesSequentially(TestNG.java:1284)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1209)
	at org.testng.TestNG.runSuites(TestNG.java:1124)
	at org.testng.TestNG.run(TestNG.java:1096)
	at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:132)
	at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:236)
	at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:81)