正在将base64编码映像上载到服务器-400服务器错误

我正在将base64编码的图像上载到 HelpScout server 使用JSON有效载荷,使用凌空飞行。这种回归 com.android.volley.serverror服务器错误 和 状态码400 . 我将图像编码如下:

var imageEncoded = ""
            try {
                val bitmap = MediaStore.Images.Media.getBitmap(context?.contentResolver, uri)
                //val bitmap = BitmapFactory.decodeFile(path)
                val stream = ByteArrayOutputStream()
                bitmap.compress(Bitmap.CompressFormat.JPEG, 70, stream)
                val imageBytes = stream.toByteArray()
                imageEncoded = Base64.encodeToString(imageBytes, Base64.DEFAULT)
            } catch (e: Exception) {
                e.printStackTrace()
            }

我已经问了几个问题,但没什么运气。下面是我正在使用的截击法:

public static void volleyRowJsonPostRequest(Context context,String url, JSONObject object,final Map<String, String> headers, final VolleyTaskListener taskListener) {
        final JsonObjectRequest jsObjRequest = new JsonObjectRequest(Request.Method.POST, url, object,
                new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        try {
                            taskListener.onTaskComplete(response.toString());
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        NetworkResponse networkResponse = error.networkResponse;
                        if (networkResponse != null)
                            taskListener.onTaskFailed(networkResponse.statusCode);

                    }
                }
        ){
            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                return headers;
            }
        };

        jsObjRequest.setRetryPolicy(new DefaultRetryPolicy(
                60000,
                DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
                DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
        jsObjRequest.setShouldCache(false);
        Volley.newRequestQueue(context).add(jsObjRequest);
    }

jsonObject是:

{
  "subject": "some test value",
  "mailboxId": 170715,
  "type": "email",
  "status": "active",
  "customer": {
    "email": "mymailaddress@mail.com"
  },
  "threads": [
    {
      "type": "customer",
      "text": "some test value",
      "customer": {
        "email": "mymailaddress@mail.com"
      },
      "attachments": [
        {
          "fileName": "Screenshot_20181005-160109.png",
          "mimeType": "image\/png",
          "data": "base64 encoded string goes here"
        }
      ]
    }
  ],
  "tags": [
    "Swytch",
    "Help"
  ]

}