Errors with In App Purchase plugin

I have trouble with BILLING connected with this plugin https://ionicframework.com/docs/native/in-app-purchase

I add my manifest.json with app key to src folder and add some copy stuff in angular.json and file is copied automaticly to www folder when I build version to run it on device. But in debug mode I get this error:

D/google.payments: Unable to read manifest file:java.io.FileNotFoundException: www/manifest.json

when I try to initialize my billings by get a products list

    this.iap
      .getProducts(['productId'])
      .then((products) => {
        console.log(products);
      })
      .catch(
        (err) => {
          console.log(err);
        }
      );

error from promise catch part is

{ code: -2, message: 'Billing cannot be initialized', errorCode: -2 }

I have all permisions in AndroidManifest.xml witch is

android:requestLegacyExternalStorage="true"
...
<uses-permission android:name="android.permission.BILLING" />
<uses-permission android:name="com.android.vending.BILLING" />

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

My manifest.json have format:

{
"play_store_key": "my base 64 code from Uncle Google Play Storage"
}

So I don’t have a clue about what is wrong. I use Ionic 5 and ofcurse forced by Uncle Google AndroidX

I’m having the same problem
{“code”: - 2, “message”: “Unable to initialize billing”, “error code”: - 2}

In cordova it was solved with hooks and it worked perfect, do not believe in capacitor improvements.