Protractor test cases are not executing on real android device using appium

I am trying to test android webapp using appium, I am facing below issue

(node:4328) [DEP0022] DeprecationWarning: os.tmpDir() is deprecated. Use os.tmpdir() instead.
[14:39:04] I/launcher - Running 1 instances of WebDriver
[14:39:04] I/hosted - Using the selenium server at http://localhost:4723/wd/hub
[14:39:50] E/launcher - An unknown server-side error occurred while processing the command. Original error: Could not proxy command to remote server.

Appium Server Log

[JSONWP Proxy] Proxying [GET /status] to [GET http://127.0.0.1:8000/wd/hub/status] with no body
[JSONWP Proxy] Got unexpected response:

[Chromedriver] Chromedriver exited unexpectedly with code null, signal SIGTERM
[Chromedriver] Changed state to ‘stopped’
[Chromedriver] ProxyRequestError: Could not proxy command to remote server. Original error: 502 - “\n\n\n\n\n \n \n \n \n \n\n\n\n\n \n \n \n \n
\n\n\n \n \n \n
\n \n \n
\n\n\n\n\n\n \n \n \n
\n Cannot Connect.\n
\n\n\n\n\n \n \n \n
\n The Proxy received an invalid response.\n
\n\n\n\n\n \n \n \n
\n URL: http://127.0.0.1:8000/wd/hub/status
\nClient IP Address: 131.199.38.224
\nClient URL: http://127.0.0.1:8000/wd/hub/status
\nProxy: la3wgus01
\n
\n\n\n\n\n\n \n \n \n \n \n \n
\n
\n Use and Monitoring of Computing Resources\n
\n
\n\n\n\n \n \n \n \n \n \n
\n If you feel you have reached this site in error, please contact the IT Service Desk at (319) 295-2000.\n
\n generated 2018-02-27 16:39:46 by McAfee Web Gateway\n
\n appium\n
\n\n
\n\n\n\n”
at JWProxy.proxy$ (C:\Users\ssomiche\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\appium-base-driver\lib\jsonwp-proxy\proxy.js:152:13)
at tryCatch (C:\Users\ssomiche\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\babel-runtime\regenerator\runtime.js:67:40)
at GeneratorFunctionPrototype.invoke [as _invoke] (C:\Users\ssomiche\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\babel-runtime\regenerator\runtime.js:315:22)
at GeneratorFunctionPrototype.prototype.(anonymous function) [as throw] (C:\Users\ssomiche\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\babel-runtime\regenerator\runtime.js:100:21)
at GeneratorFunctionPrototype.invoke (C:\Users\ssomiche\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\babel-runtime\regenerator\runtime.js:136:37)
at
[AndroidDriver] Shutting down Android driver
[ADB] Getting connected devices…
[ADB] 1 device(s) connected

capabilities: {
platformName: ‘Android’,
platformVersion: ‘7.0’,
deviceName: ‘28e5dd470169b530’,
automationName: ‘UiAutomator2’,
browserName: “”,
autoWebview: true,
app: appLocation,
fullReset: true,
enablePerformanceLogging: true
},

Android webview code
private String launchUrl = “file:///android_asset/www/index.html”;
private WebView webView;

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_stage);

    webView = (WebView) findViewById(R.id.webView);
    WebSettings webSettings = webView.getSettings();
    webSettings.setJavaScriptEnabled(true);
    webSettings.setAllowFileAccessFromFileURLs(true);
    WebView.setWebContentsDebuggingEnabled(true);

    /*if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        WebView.setWebContentsDebuggingEnabled(true);
    }*/
    webView.loadUrl(launchUrl);
    webView.setWebViewClient(new StageWebViewClient());
}

$ appium -v
1.7.2

latest chromedriver