Blank screeen on Andoid app

Hello,

First time Ionic user. I have an Angular 2 app which I’ve been trying to migrate to Ionic. Everything is OK, but today after building the app with using these instructions: http://ionicframework.com/docs/intro/deploying/ I installed it on a Samsung S7 running Android 7.0 and an S5 with 6.0.1.
Running it showed a splash screen and then a blank white screen. If I do ionic serve it runs great in the browser.

How can this be fixed?

I read that installing cordova crosswalk helped with version 4.1 … but that doesn’t seem applicable in my case.

config.xml

<preference name="ScrollEnabled" value="false" />
<preference name="android-minSdkVersion" value="16" />
<preference name="webviewbounce" value="false" />
<preference name="UIWebViewBounce" value="false" />
<preference name="DisallowOverscroll" value="true" />
<preference name="BackupWebStorage" value="none" />
<preference name="SplashMaintainAspectRatio" value="true" />
<preference name="FadeSplashScreenDuration" value="300" />
<preference name="ShowSplashScreen" value="false" />
<preference name="SplashShowOnlyFirstTime" value="false" />
<preference name="SplashScreen" value="screen" />
<preference name="SplashScreenDelay" value="3000" />

package.json

“dependencies”: {
"@angular/common": “4.4.3”,
"@angular/compiler": “4.4.3”,
"@angular/compiler-cli": “4.4.3”,
"@angular/core": “4.4.3”,
"@angular/forms": “4.4.3”,
"@angular/http": “4.4.3”,
"@angular/platform-browser": “4.4.3”,
"@angular/platform-browser-dynamic": “4.4.3”,
"@ionic-native/core": “4.3.0”,
"@ionic-native/splash-screen": “4.3.0”,
"@ionic-native/status-bar": “4.3.0”,
"@ionic/storage": “2.0.1”,
“angularfire2”: “^5.0.0-rc.1”,
“cordova-android”: “^6.2.3”,
“cordova-ios”: “^4.5.1”,
“cordova-plugin-device”: “^1.1.4”,
“cordova-plugin-ionic-webview”: “^1.1.14”,
“cordova-plugin-splashscreen”: “^4.0.3”,
“cordova-plugin-statusbar”: “git+https://github.com/apache/cordova-plugin-statusbar.git”,
“cordova-plugin-whitelist”: “^1.3.1”,
“firebase”: “^4.5.0”,
“ionic-angular”: “3.7.1”,
“ionic-plugin-keyboard”: “^2.2.1”,
“ionicons”: “3.0.0”,
“rxjs”: “5.4.3”,
“sw-toolbox”: “3.6.0”,
“zone.js”: “0.8.18”
},