ionic 4 built apk not installing

I built my ionic app into apk successfully using the --prod and --release flag before signing the Apk. everything happened without error. But if i try to install the app on my phone i get an error :

" App not installed."

i really dont know what to do again. My phone is running Android 8.1.0 and my ionic info is displayed below:

Ionic:

   ionic (Ionic CLI)             : 4.7.1 (C:\Users\Joxeff.DESKTOP-NMC7DC1\AppData\Roaming\npm\node_modules\ionic)
   Ionic Framework               : @ionic/angular 4.11.10
   @angular-devkit/build-angular : 0.801.3
   @angular-devkit/schematics    : 8.1.3
   @angular/cli                  : 8.1.3
   @ionic/angular-toolkit        : 2.1.2

Cordova:

   cordova (Cordova CLI) : 9.0.0 (cordova-lib@9.0.1)
   Cordova Platforms     : android 8.1.0
   Cordova Plugins       : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 4.1.3, (and 6 other plugins)

System:

   Android SDK Tools : 26.1.1 (C:\Users\Joxeff.DESKTOP-NMC7DC1\AppData\Local\Android\Sdk)
   NodeJS            : v12.13.0 (C:\Program Files (x86)\nodejs\node.exe)
   npm               : 6.12.0
   OS                : Windows 10

Solution

Check your config.xml and change the app id.
Or uninstall the app with the same app id.

<widget id="com.domain.app" version="0.0.1" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">

If you already have an app with the same id it can't be installed on android.

Had the same issue and after deleting the old version of the app i could install the new app.