My ionic app is working with --devapp. But my app turn just white screen after build

This is my first time using Ionic, also my first time asking question in a forum. So please, tell me if I need to supply or add more info to make my question clearer.

What I meant by did not work is my app got white screen after I built it on my android. But somehow when I used --devapp it is working just fine.

cordova @ 9.0.0
node v12.13.0


Ionic CLI : 5.4.5 (/usr/local/lib/node_modules/ionic)
Ionic Framework : @ionic/angular 4.11.4
@angular-devkit/build-angular : 0.801.3
@angular-devkit/schematics : 8.1.3
@angular/cli : 8.1.3
@ionic/angular-toolkit : 2.0.0


Cordova CLI : not installed
Cordova Platforms : not available
Cordova Plugins : not available


cordova-res : 0.8.1
native-run : 0.2.9 (update available: 0.3.0)


Android SDK Tools : 26.1.1 (/Users/alvin/Library/Android/sdk)
NodeJS : v12.13.0 (/usr/local/bin/node)
npm : 6.12.0
OS : macOS Sierra