cant upload a photo file with retrofit in android java

Question

I have a post API which accept photo with one multipart photo and a string title as a body now I want to use retrofit to upload photo which I got error with null response

my interface code is :

public interface UploadPhotoApi {
@Multipart
@POST("files/")
Call<FileUpdloadResponse> upload(
        @Part MultipartBody.Part file,
        @Part("title") RequestBody title
        );}

and my code for uploading file is :

File file = FileUtils.getFileFromUri(getContext(),uri);//make file from uri
RequestBody requestFile =
                    RequestBody.create(file,MediaType.parse("image/*"));
            MultipartBody.Part body =
                    MultipartBody.Part.createFormData("image", file.getName(), requestFile);
            //String title = file.getName();
            RequestBody title =
                    RequestBody.create(
                            file.getName(),MediaType.parse("text/plain"));


            Call<FileUpdloadResponse> call = uploadPhotoApi.upload(body,title);
            call.enqueue(new Callback<FileUpdloadResponse>() {
                @Override
                public void onResponse(Call<FileUpdloadResponse> call, Response<FileUpdloadResponse> response) {
                    try {
                        pk = response.body().getPk();
                        imageView.setImageURI(uri);
                        makeVisible(getString(R.string.photo_uploaded));
                    }catch (Exception e){

                        Log.i("Log12", "exception2 is" + e.toString());
                        makeVisible(getString(R.string.photo_not_uploaded));
                    }
                }

                @Override
                public void onFailure(Call<FileUpdloadResponse> call, Throwable t) {
                    makeVisible(getString(R.string.photo_not_uploaded));

                    Log.i("Log12", "failure is" + t.toString());
                }
            });

If I get a correct response from server it should have pk in response model. but pk is null so catch part run and show error uploading to user ...

I tried many things in similar questions but I didn't found any right solution to solve my problem.

and file utils is this code :

So I'm sorry if I asked a repeated question .... for example I read this article but didn't helped: How to upload an image file in Retrofit 2