"Ionic monitoring syncmaps" not working, getting "Source Mapped: NO"

I am trying to Monitor ionic app, but Monitoring Event Log displays:

Error Log
    Exception Detail
        Error: Uncaught (in promise): undefined        "Source Mapped: NO"

How do I change Source Mapped: NO to Source Mapped: YES ?

I followed this article

Notice that the Exception Detail contains references to main.js , and on the right the information shows Source Mapped value as NO . This means that the source maps have not been configured/synced with the Ionic Pro services. To do that, run the command below (using Ionic CLI 3.9.0 or greater) in your terminal:

ionic monitoring syncmaps

Is the version number from config.xml?

const IonicPro = Pro.init("12345678", {
     appVersion: "2.0.0"

$ ionic monitoring syncmaps

Using existing sourcemaps in ./.sourcemaps
✔ Syncing sourcemaps: 45 / 45 - done!
[OK] Sourcemaps synced!
Pro ID      : 12345678
Version     : 2.0.0
Package ID  : com.app.my
Snapshot ID : not set

See the Error Monitoring docs for usage information and next steps: https://ionicframework.com/docs/pro/monitoring

$ ionic info
✔ Gathering environment info - done!


  ionic (Ionic CLI)  : 4.2.1
  Ionic Framework    : ionic-angular 3.9.2
  @ionic/app-scripts : 3.2.1


  cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
  Cordova Platforms     : android 7.1.4, browser 5.0.4, ios 4.5.5
  Cordova Plugins       : cordova-plugin-ionic 4.0.0, cordova-plugin-ionic-keyboard 2.0.5, cordova-plugin-ionic-webview 1.1.1, (and 20 other plugins)