appium: iOS Appium giving error: TypeError: Cannot read property 'wasThrown' of undefined

Problem: I have upgraded XCode to 9 and Appium to 1.7/1.6.5 and trying to execute few test cases on mobile web. Code:

_DesiredCapabilities capabilities = new DesiredCapabilities();
capabilities.setCapability("deviceName", "iPhone");
capabilities.setCapability("udid", "<udid>");
capabilities.setCapability("platformName", "iOS");
capabilities.setCapability("automationName", "XCUITest");
capabilities.setCapability("browserName", "Safari");
capabilities.setCapability("newCommandTimeout",180);
capabilities.setCapability("webkitResponseTimeout", 70000);
capabilities.setCapability("networkConnectionEnabled",true);
capabilities.setCapability("--session-override",true);
		
driver = new RemoteWebDriver(new URL("http://127.0.0.1:4723/wd/hub"), capabilities);
driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
Thread.sleep(5000);
driver.get("https://<url>");
Thread.sleep(10000);
driver.findElement(By.xpath("//*[@id='<>']")).click();_

Sometimes the test case run properly but sometimes it gives error as mentioned below: Sep 22, 2017 9:19:00 PM org.openqa.selenium.remote.ProtocolHandshake createSession INFO: Detected dialect: OSS Exception in thread “main” org.openqa.selenium.remote.UnreachableBrowserException: Error communicating with the remote browser. It may have died. Build info: version: ‘3.5.3’, revision: ‘', time: '2017-08-29T12:42:44.’ System info: host: ‘MacBook-Pro.local’, ip: ‘’, os.name: ‘Mac OS X’, os.arch: ‘x86_64’, os.version: ‘10.12.6’, java.version: ‘1.8.0_40’ Driver info: driver.version: RemoteWebDriver Capabilities [{networkConnectionEnabled=true, webkitResponseTimeout=70000, --session-override=true, databaseEnabled=false, deviceName=iPhone, platform=MAC, newCommandTimeout=180, webStorageEnabled=false, locationContextEnabled=false, automationName=XCUITest, browserName=Safari, takesScreenshot=true, javascriptEnabled=true, udid=<udid>, platformName=MAC}] Session ID: at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:667) at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:416) at org.openqa.selenium.remote.RemoteWebDriver.findElementByXPath(RemoteWebDriver.java:518) at org.openqa.selenium.By$ByXPath.findElement(By.java:361) at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:408) at com.appium_ios11.testExec.main(testExec.java:64) Caused by: org.apache.http.conn.HttpHostConnectException: Connect to 127.0.0.1:4723 [/127.0.0.1] failed: Connection refused at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:159) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:359) at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:381) at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:237) at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185) at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89) at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:111) at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185) at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:72) at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56) at org.openqa.selenium.remote.internal.ApacheHttpClient.fallBackExecute(ApacheHttpClient.java:139) at org.openqa.selenium.remote.internal.ApacheHttpClient.execute(ApacheHttpClient.java:87) at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:161) at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:646) … 5 more Caused by: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:589) at org.apache.http.conn.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:75) at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142) … 18 more

Also, on looking at appium server logs, I get the below error:

_[debug] [RemoteDebugger] Webkit response timeout: 70000
[debug] [RemoteDebugger] Receiving WebKit data: {"result":{"result":{"type":"string","value":"{\"status\":0,\"value\":null}"},"wasThrown":false},"id":3}
[debug] [RemoteDebugger] Found handler for message '3'
[debug] [RemoteDebugger] Received result for atom 'click' execution: null
[debug] [MJSONWP] Responding to client with driver.click() result: null
[HTTP] <-- POST /wd/hub/session/**/element/5000/click 200 942 ms - 76 
[debug] [RemoteDebugger] Receiving WebKit data: {"method":"Canvas.canvasMemoryChanged","params":{"canvasId":"canvas:0.3","memoryCost":32000}}
TypeError: Cannot read property 'wasThrown' of undefined
    at WebKitRpcClient.receive (../../lib/webkit-rpc-client.js:117:38)
    at emitTwo (events.js:106:13)
    at WebSocket.emit (events.js:191:7)
    at Receiver.ontext (/usr/local/lib/node_modules/appium/node_modules/ws/lib/WebSocket.js:841:10)
    at /usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:536:18
    at Receiver.applyExtensions (/usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:371:5)
    at /usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:508:14
    at Receiver.flush (/usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:347:3)
    at Receiver.finish (/usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:541:12)
    at Receiver.expectHandler (/usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:499:31)
    at Receiver.add (/usr/local/lib/node_modules/appium/node_modules/ws/lib/Receiver.js:103:24)
    at Socket.realHandler (/usr/local/lib/node_modules/appium/node_modules/ws/lib/WebSocket.js:825:20)
    at emitOne (events.js:96:13)
    at Socket.emit (events.js:188:7)
    at readableAddChunk (_stream_readable.js:176:18)
    at Socket.Readable.push (_stream_readable.js:134:10)
    at TCP.onread (net.js:548:20)_

Can any one please help…