问Firebase匿名登录异常

EN

private void signInAnonymously() {
    mAuth.signInAnonymously().addOnSuccessListener(this, new OnSuccessListener<AuthResult>() {
        @Override
        public void onSuccess(AuthResult authResult) {
            FirebaseUser currentUser = mAuth.getCurrentUser();
            Log.d("onStart ",currentUser.getUid());


            // do your stuff
            Toast.makeText(MainActivity.this, "Authorisation successful", Toast.LENGTH_SHORT).show();
        }
    })
            .addOnFailureListener(this, new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception exception) {
                    Log.e("url", "signInAnonymously:FAILURE", exception);
                }
            });
}