After using --prod angular functions not working

After using ionic cordova build android --prod
my app taking minimum time to load but the functionalities e.g. the function behind the login button is not working.So the next welcome page where the menus are given, are not appearing.Please help…

Environment Details:

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

@ionic/cli-utils  : 1.19.2
ionic (Ionic CLI) : 3.20.0

global packages:

cordova (Cordova CLI) : 8.0.0

local packages:

@ionic/app-scripts : 3.1.9
Cordova Platforms  : android 7.0.0
Ionic Framework    : ionic-angular 3.9.2


Android SDK Tools : 26.1.1
Node              : v8.11.2
npm               : 5.6.0
OS                : Windows 7

Environment Variables:

ANDROID_HOME : C:\Users\Abhik\AppData\Local\Android\sdk


backend : pro