firebase-phone-authentication | Authentication library

I am trying to implement phone auth using firebase. I was going through this guide -> https://fireship.io/lessons/firebase-phone-authentication-with-angular-4-tutorial/

I'm having react-native app that is using Firebase to verify user phone numbers. So far, I was testing this by the use of test phone number added to Firebase console and it was working fine. Now, I'm trying to prepare my application for release and I was trying to generated signed release and test phone verification. I did the following:

1. generated release keystore and added it to android/app
2. added these parameters to build.gradle android.signincConfigs.release storeFile file('my-release-key.keystore') storePassword 'my-password' keyAlias 'my-alias' keyPassword 'my-password' (basically following these steps https://medium.com/@raguct25/how-to-generate-signed-or-released-apk-file-from-react-native-252bdd1915a2)
3. used keytool -list ... command to get SHA-1 and add it to Firebase console under my project.
4. download new google-services.json and added it under android/app
5. • generate build using ./gradlew assembleRelease
   • generate signed APK using Android Studio
   • run release in simulator using react-native run-android —variant=release

In each of these builds when firebase is trying to authenticate it's causing app to crash when request to send OTP code is made. My implementation is similar to approach described here https://heartbeat.fritz.ai/implement-firebase-phone-authentication-in-react-native-apps-237959027611

App works well with test phone number.

Error is happening within this code silently, e.g. catch block doesn't catch any error:

I'm implementing FirebaseAuth verify phone adapting this guide https://medium.com/@tapanrgohil/firebase-phone-authentication-in-flutter-with-bloc-pattern-4ddc2d43d76c as I don't want to sign in but just link the new PhoneAuthentication to existing user and I'm using AuthenticationBloc instead of Losing Bloc es in the guide.

I start the phone verification process in PaymentScreen and I tried providing AuthenticationBloc directly in PaymentScreen's MultiBlocProvider, thinking create a new AuthenticationBloc but the error is the same.

In AuthenticationBloc basically an internal StreamController takes care of all phone verification events. Incoming States in PaymentScreen's BlocListener just react popping and showing dialogs as in case of AutoRetrieveCodeTimeout showing manual otp insert dialog, errors, wrong otp and so on. To find out what's causing the bad state I first commented out all context pops just to make sure it wast that, and then I commented out all .close() in the stream.

These are the prints from console: