Push notification on android: PushNotification plugin is not installed

Ionic Framework ionic-v3
1

Hi everyone,
I integrated the push service into my ionic3 app. iOS works succesfully but on Android platform I have a problem during registration:

In the log I see this message

Native: tried calling PushNotification.init, but the PushNotification plugin is not installed.

My source code:

let pushOptions: PushOptions = {
  android: { senderID: Config.Prop.FIREBASE_SENDER_ID },
  ios: { alert: 'true', badge: 'true', sound: 'true' },
  windows: {}
};
const pushObject: PushObject = this.push.init(pushOptions);

pushObject.on('registration').subscribe((registration: any) => {
  console.log("PUSH REGISTRATION BEGIN...", registration.registrationId)
  this.storage.set(Config.Storage.PUSH_TOKEN, registration.registrationId).then(val => {
	console.log('push notification token saved');
  })
})

I tried to reinstall the plugin but after this I receive this build error:

> Failed to apply plugin [class 'com.google.gms.googleservices.GoogleServicesPlugin']
> For input string: "+"

my project.properties is:

target=android-26
android.library.reference.1=CordovaLib
android.library.reference.2=app
cordova.system.library.1=com.squareup.okhttp3:okhttp-urlconnection:3.10.0
cordova.system.library.2=com.android.support:support-v4:24.1.1+
cordova.system.library.3=com.google.android.gms:play-services-analytics:+
cordova.system.library.4=com.android.support:support-v13:26.+
cordova.system.library.5=me.leolin:ShortcutBadger:1.1.17@aar
cordova.system.library.6=com.google.firebase:firebase-messaging:11.6.2
cordova.gradle.include.1=phonegap-plugin-push/acronym-push.gradle

Could you please help me?

Thanks in advance