Failed to load webpage with error: The URL can’t be shown when you try to reload html file (local file)

I am trying to reload the app by calling with a load request URL by calling in our custom function written in Objective C -
- (void)reloadApp:(CDVInvokedUrlCommand*)command{
............
...............
.
[self.webViewEngine loadRequest:request];
}

which in turn call - (id)loadRequest:(NSURLRequest *)request function in CDVWKWebViewEngine.m

but app fails to reload and fails with an error Failed to load webpage with error: The URL can’t be shown when you try to reload

I have set these parameters in config.xml

allow-navigation href="http://127.0.0.1:8080/*" />
preference name="CordovaWebViewEngine" value="CDVWKWebViewEngine" />
feature name="CDVWKWebViewEngine">

/feature>

Is it a problem with WKWebView or am I missing something ?.I am using "cordova-plugin-ionic-webview" of version 1.2.1.I tried with latest beta 2.0 but that does not even load my app in the beginning .Any help would be appreciated