recyclerView.addOnScrollListener - "retrofit pagination with MVVM" is loading the same response/list

I am using blogger API, retrofit, and MVVM in my app, I trying to use pagination to load more posts when user is scrolling, the problem happening here the response is loading it self "the same list / same ten posts is loading again"

here's my code [PostViewModel]

public class PostViewModel extends ViewModel {

    public static final String TAG = "PostViewModel";


    public MutableLiveData<PostList> postListMutableLiveData = new MutableLiveData<>();
    public MutableLiveData<PostList> postListByLabelMutableLiveData = new MutableLiveData<>();
    public MutableLiveData<String> finalURL = new MutableLiveData<>();
    public MutableLiveData<String> token = new MutableLiveData<>();

    public void getPosts(){


        if (token.getValue() != "") {
            finalURL.setValue(finalURL.getValue() + "&pageToken=" + token.getValue());
        }
        if (token == null) {
            return;
        }

        PostsClient.getINSTANCE().getPostList().enqueue(new Callback<PostList>() {
            @Override
            public void onResponse(@NotNull Call<PostList> call, @NotNull Response<PostList> response) {

                PostList list = response.body();

                if (list.getItems() != null) {
                    token.setValue(list.getNextPageToken());
                    postListMutableLiveData.setValue(list);
                }

                Log.i(TAG,response.body().getItems().toString());
            }

            @Override
            public void onFailure(Call<PostList> call, Throwable t) {
                Log.e(TAG,t.getMessage());
            }
        });

    }


    public void getPostListByLabel(){

        PostsByLabelClient.getINSTANCE().getPostListByLabel(finalURL.getValue()).enqueue(new Callback<PostList>() {
            @Override
            public void onResponse(Call<PostList> call, Response<PostList> response) {
                postListByLabelMutableLiveData.setValue(response.body());
            }

            @Override
            public void onFailure(Call<PostList> call, Throwable t) {

            }
        });
    }
}

HomeFragment Class "The main page"

public class HomeFragment extends Fragment {

    private PostViewModel postViewModel;
    public static final String TAG = "HomeFragment";
    private RecyclerView recyclerView;
    private PostAdapter postAdapter;
    private List<Item> itemArrayList;
    private boolean isScrolling = false;
    private int currentItems, totalItems, scrollOutItems, selectedIndex;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {

        postViewModel = new ViewModelProvider(this).get(PostViewModel.class);
        postViewModel.getPosts();

        View root = inflater.inflate(R.layout.fragment_home, container, false);

        itemArrayList = new ArrayList<>();

        recyclerView = root.findViewById(R.id.homeRecyclerView);
        postAdapter = new PostAdapter(getContext(),itemArrayList);

        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext());
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(linearLayoutManager);
        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext()
                , linearLayoutManager.getOrientation());
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.addItemDecoration(dividerItemDecoration);
        recyclerView.setAdapter(postAdapter);

//                textView.setText(s);
                postViewModel.postListMutableLiveData.observe(HomeFragment.this, new Observer<PostList>() {
                    @Override
                    public void onChanged(PostList postList) {
                        itemArrayList.addAll(postList.getItems());
                        postAdapter.notifyDataSetChanged();
                    }
                });


        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                    isScrolling = true;



            }

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                if (dy > 0) {
                    currentItems = linearLayoutManager.getChildCount();
                    totalItems = linearLayoutManager.getItemCount();
                    scrollOutItems = linearLayoutManager.findFirstVisibleItemPosition();
                    if (isScrolling && (currentItems + scrollOutItems == totalItems)) {
                        isScrolling = false;
                        postViewModel.getPosts();
                        postAdapter.notifyDataSetChanged();


                    }
                }

            }
        });


        return root;

    }
}

’More explanation

on PostViewModel I created one variable

public MutableLiveData<String> token = new MutableLiveData<>();

This token that represents a new page/response will carry "each page has a list / ten new posts"

on HomeFragment

I created three integer values

private int currentItems, totalItems, scrollOutItems, selectedIndex;

and one boolean

private boolean isScrolling = false;

then I used recyclerView.addOnScrollListener

with this way to load the next ten posts, but it's not working like I said before, its loading the same result/list

The result on imgur.com

from recyclerView.addOnScrollListener - "retrofit pagination with MVVM" is loading the same response/list