Flutter Phone authentication works fine on emulator but not working on real device (Android)

Question

Below is my Phone Authentication code. On a real device, when I run my app after sending a phone number to Auth.verifyPhoneNumber() function it crashes in 2 seconds. But it is working fine on emulator. I don't know what is going to happen in the code please help me. Sorry for the bad English I am not a native speaker.

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutterphoneauth/datamodel/datamodel.dart';

import 'package:toast/toast.dart';

class AuthService {
  String _phoneNumber;
  String _verificationId;
  String _smsCode;
  String _message;

  final FirebaseAuth _auth = FirebaseAuth.instance;

  String get phoneNumber1 => _phoneNumber;
  String get verificationId => _verificationId;
  String get smsCode => _smsCode;
  String get message => _message;

  Future<void> verifyPhoneNumber(
      String phoneNumber, BuildContext context) async {
    Toast.show("Run", context);
    try {
      PhoneVerificationCompleted verificationCompleted =
          (PhoneAuthCredential phoneAuthCredential) async {
        Toast.show("verification done", context);
        // UserCredential _userCredential =
        //     await _auth.signInWithCredential(phoneAuthCredential);
      };

      PhoneVerificationFailed verificationFailed =
          (FirebaseAuthException authException) async {
        print('Auth Exception Occured');
        // throw Exception(authException.message);
        // _message =
        //     'Phone number verification failed. Code: ${authException.code}. Message: ${authException.message}';
      };

      PhoneCodeSent codeSent =
          (String verificationId, [int forceResendingToken]) async {
        print('SMS Sent');
        _verificationId = verificationId;
      };

      PhoneCodeAutoRetrievalTimeout codeAutoRetrievalTimeout =
          (String verificationId) async {
        print('SMS Auto Retrieval Timeout');
        _verificationId = verificationId;
      };

      await _auth.verifyPhoneNumber(
          phoneNumber: "+92$phoneNumber",
          timeout: const Duration(seconds: 5),
          verificationCompleted: verificationCompleted,
          verificationFailed: verificationFailed,
          codeSent: codeSent,
          codeAutoRetrievalTimeout: codeAutoRetrievalTimeout);
    } catch (e) {
      database.msgError = e.toString();
    }
  }

  // Example code of how to sign in with the phone.
  Future signInWithPhoneNumber(String smsCode) async {
    final AuthCredential credential = PhoneAuthProvider.credential(
      verificationId: _verificationId,
      smsCode: smsCode,
    );
    return (await _auth.signInWithCredential(credential)).user;
  }
}

Answer 1

I found a solution and you can say reason actually I try to send code again and again on the same number that's a reason firebase not send code on my real device again and again. and you can check more about of security rules on official documentation

https://firebase.google.com/docs/auth/android/phone-auth#security-concerns