//used for signing the user private void signInWithPhoneAuthCredential(PhoneAuthCredential credential) { mAuth.signInWithCredential(credential) .addOnCompleteListener(VerifyPhoneActivity.this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { //verification successful we will start the profile activity Intent intent = new Intent(VerifyPhoneActivity.this, ProfileActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK); startActivity(intent); } else { //verification unsuccessful.. display an error message String message = "Somthing is wrong, we will fix it soon..."; if (task.getException() instanceof FirebaseAuthInvalidCredentialsException) { message = "Invalid code entered..."; } Toast.makeText(VerifyPhoneActivity.this,message,Toast.LENGTH_SHORT).show(); } } }); }