ionic 2 local notification not showing

I'm working with ionic 2 local notification for the first time. I've followed this YouTube tutorial.

When I test my app in Xcode, I'm getting a warning message below and the notification message doesn't show... not sure why.

WARN: Unknown property: at

I have installed

ionic cordova plugin add de.appplant.cordova.plugin.local-notification

npm install --save @ionic-native/local-notifications

and added the plugin as a provider in src/app/app.module.ts

I have following code:

home.html:

<button ion-button (click)=myNotifications()>Test</button>

app.module.ts

import { Component } from '@angular/core';
import { NavController, Platform, ActionSheetController, AlertController } from 'ionic-angular';
import { ScreenOrientation } from '@ionic-native/screen-orientation';
import { LocalNotifications } from '@ionic-native/local-notifications';


    export class HomePage {

      constructor(public navCtrl: NavController,
                  public platform: Platform,
                  private screenOrientation: ScreenOrientation,
                  private localNotifications: LocalNotifications,
                  public alertCtrl: AlertController ) {

                    this.platform.ready().then((ready) =>{
                      this.localNotifications.on('click', (notification, state) => {
                        let json = JSON.parse(notification.data);

                        let alert = this.alertCtrl.create({
                          title: notification.title,
                          message: json.fullMsq
                        });
                        alert.present();
                      });
                    });
      }

      myNotifications() {

        this.localNotifications.schedule({
          id: 1,
          title: 'ABC Meeting Notification',
          text: 'ABC Meeting will start in 20 mins',
          at: new Date(new Date().getTime() + 20*60*1000),
          data: { fullMsq: 'this is the full notification message' }
        })
      }

    }

Refer Notification Demo: https://github.com/husainsr/Ionic3_Notification May it Proves Helpful to you.