In this line the intercom cordova plugin is referencing a package version that is not available anymore on JCenter or Google Maven repositories. That cause an error when building the app:
Could not find any version that matches com.android.tools.build:gradle:2.3.+.
I’m using cordova-android v6.4.0 and can’t update right now because other plugins that I’m using.
If I change the referenced line to use
..gradle:3.0.0 it works ok. Can you consider update that dependency?