Ionic 4 Application error (Connection to server was unsuccessfull error)

[ASHFAQPATWARI]

Description:

Ionic 4 app works in android/ios emulator but does not work on android/ios device with command ionic cordova run android --prod
It shows a white screen for long time and then says: Application Error (Connection to server was unsuccessfull (file:///android_asset/www/index.html)

Steps to Reproduce:

1. Clone ionic conference app (core update branch)
2. Try to run on device with command ionic cordova run android --prod

Output:

My ionic info:

cli packages: (C:\Users\apatwari\AppData\Roaming\npm\node_modules)

   @ionic/cli-utils  : 2.0.0-rc.5
   ionic (Ionic CLI) : 4.0.0-rc.5

global packages:

   cordova (Cordova CLI) : 6.5.0

local packages:

   @angular-devkit/core       : 0.6.0
   @angular-devkit/schematics : 0.6.0
   @angular/cli               : 6.0.3
   @ionic/schematics-angular  : 1.0.0-rc.6
   Cordova Platforms          : android 6.4.0
   Ionic Framework            : @ionic/angular 4.0.0-alpha.6

System:

   NodeJS : v9.11.1
   npm    : 5.6.0
   OS     : Windows 7

Other Information:

[imhoffd]

We're waiting on some changes to the webview plugin. Android device/emulator support isn't quite ready yet. See ionic-team/cordova-plugin-ionic-webview#104

[ASHFAQPATWARI]

@dwieeb But we have seen videos and screenshots from @mhartington in his tweets about ionic 4 performance which were on real devices. Thanks for the update though.

[mhartington]

Hey there! The demos you've been seeing have been testing out new things and have mostly been on iOS or in the browser. @dwieeb is correct that android currently has a few issues. We are working on the solution in ionic-team/cordova-plugin-ionic-webview#104, but until that gets merged in, nothing is production ready

[ASHFAQPATWARI]

@mhartington I have tried to run the sidemenu starter/ ionic 4 conference app in IOS devices and I am getting the same issue there also. So for me, even IOS is not working.

[imhoffd]

Let's track this here: #3279