Unable to create production build

here is the out put of my ionic info

cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils  : 1.19.1
ionic (Ionic CLI) : 3.19.1

global packages:

cordova (Cordova CLI) : 8.0.0

local packages:

@ionic/app-scripts : 3.1.0
Cordova Platforms  : android 6.4.0 ios 4.5.4
Ionic Framework    : ionic-angular 3.9.2

System:

Android SDK Tools : 26.1.1
Node              : v9.2.1
npm               : 5.5.1
OS                : Linux 4.4

Environment Variables:

ANDROID_HOME : /home/user/android-sdk

Misc:

backend : pro