No access to or access to Firebase

I am not able to access Firestore documents through my Android application, so please give me the message below, even if it is enabled for anyone to access the rules of my Firebase / Firestore:

  

Missing or insufficient permissions.

It's not an Android or Java bug, but Firebase, the query goes on to say that it did not pick up and the above message is returned.

Follow the current rules:

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write;
    }
  }
}

Follow the current application:

firebaseFirestore = FirebaseFirestore.getInstance ();

        firebaseFirestore.collection ( "clients" ).document ().get ().addOnSuccessListener ( new OnSuccessListener<DocumentSnapshot> () {
            @Override
            public void onSuccess(DocumentSnapshot documentSnapshot)
            {
                    Log.i("TESTES", "Clients get");
            }
        } ).addOnFailureListener ( new OnFailureListener () {
            @Override
            public void onFailure(@NonNull Exception e)
            {
                    Log.i("TESTES", "Didnt get Clients ---> "+ e.getMessage ());
            }
        } );