Ionic 2 push ios

the main problem is phonegap-plugin-push is installed the cert is generated well but the

push.on(‘registration’, function (datas){
this._auth.setNotificationToken(datas.registrationId.toString(),device_type).subscribe((data)=> {console.log(data)});

this function is not firing at all in ios
and when starting app in iPhone is not asking for notification permission
what is my problem ?
ps:android is working with no problem

Use this:

let push = Push.init({
          android: {
            senderID: "<senderid>"
          ios: {
            alert: "true",
            badge: true,
            sound: "true"

push.on('registration', (data) => {