appium error - css selector

appium error log

org.openqa.selenium.InvalidSelectorException: Locator Strategy 'css selector' is not supported for this session
For documentation on this error, please visit: http://seleniumhq.org/exceptions/invalid_selector_exception.html
Build info: version: '3.5.3', revision: 'a88d25fe6b', time: '2017-08-29T12:42:44.417Z'
System info: host: 'Digitals-MacBook-Air.local', ip: 'fe80:0:0:0:1c03:649c:e700:4f0%en0', os.name: 'Mac OS X', os.arch: 'x86_64', os.version: '10.13.6', java.version: '1.8.0_192'
Driver info: io.appium.java_client.ios.IOSDriver
Capabilities [{app=com.sas.wefly.qa, networkConnectionEnabled=false, noReset=true, useJSONSource=true, xcodeOrgId=rudn392dnwo, databaseEnabled=false, deviceName=iPad mini 4, xcodeSigningId=iPhone Developer, platform=MAC, appium-version=1.9.1-beta2, sendKeyStrategy=grouped, newCommandTimeout=30000, platformVersion=12.1, webStorageEnabled=false, locationContextEnabled=false, automationName=XCUITest, browserName=, takesScreenshot=true, skipUnlock=true, javascriptEnabled=true, udid=12345678910, platformName=MAC, autoAcceptAlerts=true}]
Session ID: 51343f57-bfb8-4c9d-a646-e254a1e4228e
*** Element info: {Using=id, value=Sign In}

	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.createException(W3CHttpResponseCodec.java:185)
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.decode(W3CHttpResponseCodec.java:120)
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.decode(W3CHttpResponseCodec.java:49)
	at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:164)
	at io.appium.java_client.remote.AppiumCommandExecutor.execute(AppiumCommandExecutor.java:89)
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:646)
	at io.appium.java_client.DefaultGenericMobileDriver.execute(DefaultGenericMobileDriver.java:42)
	at io.appium.java_client.AppiumDriver.execute(AppiumDriver.java:1)
	at io.appium.java_client.ios.IOSDriver.execute(IOSDriver.java:1)
	at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:416)
	at io.appium.java_client.DefaultGenericMobileDriver.findElement(DefaultGenericMobileDriver.java:62)
	at io.appium.java_client.AppiumDriver.findElement(AppiumDriver.java:1)
	at io.appium.java_client.ios.IOSDriver.findElement(IOSDriver.java:1)
	at org.openqa.selenium.remote.RemoteWebDriver.findElementById(RemoteWebDriver.java:462)
	at io.appium.java_client.DefaultGenericMobileDriver.findElementById(DefaultGenericMobileDriver.java:70)
	at io.appium.java_client.AppiumDriver.findElementById(AppiumDriver.java:1)
	at io.appium.java_client.ios.IOSDriver.findElementById(IOSDriver.java:1)
	at org.openqa.selenium.By$ById.findElement(By.java:218)
	at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:408)
	at io.appium.java_client.DefaultGenericMobileDriver.findElement(DefaultGenericMobileDriver.java:58)
	at io.appium.java_client.AppiumDriver.findElement(AppiumDriver.java:1)
	at io.appium.java_client.ios.IOSDriver.findElement(IOSDriver.java:1)
	at com.sqs.PageObjectst.BasePage.click(BasePage.java:27)
	at com.sqs.PageObjectst.LogInPage.clickSignInButtonOnHomePage_aroundBody0(LogInPage.java:43)
	at com.sqs.PageObjectst.LogInPage$AjcClosure1.run(LogInPage.java:1)
	at org.aspectj.runtime.reflect.JoinPointImpl.proceed(JoinPointImpl.java:149)
	at io.qameta.allure.aspects.StepsAspects.step(StepsAspects.java:51)
	at com.sqs.PageObjectst.LogInPage.clickSignInButtonOnHomePage(LogInPage.java:43)
	at TestCases.AppSettingsTest.checkAppVersionLabelIsDisplayed(AppSettingsTest.java:25)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:108)
	at org.testng.internal.Invoker.invokeMethod(Invoker.java:661)
	at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:869)
	at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1193)
	at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:126)
	at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)
	at org.testng.TestRunner.privateRun(TestRunner.java:744)
	at org.testng.TestRunner.run(TestRunner.java:602)
	at org.testng.SuiteRunner.runTest(SuiteRunner.java:380)
	at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:375)
	at org.testng.SuiteRunner.privateRun(SuiteRunner.java:340)
	at org.testng.SuiteRunner.run(SuiteRunner.java:289)
	at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
	at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
	at org.testng.TestNG.runSuitesSequentially(TestNG.java:1301)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1226)
	at org.testng.TestNG.runSuites(TestNG.java:1144)
	at org.testng.TestNG.run(TestNG.java:1115)
	at org.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:73)
	at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:123)