Android - Receiving string from server after sending an image

I have an android app that opens a socket connection and sends an image to a python server. The image is continously received for as long as the user presses the capture button. However, what I want to do is return a string/text confirming the image has arrived to the user client.

This is my Python server that receives the image as bytes decodes and saves it to a directory then sends a message back:

from socket import *
import datetime
import cv2
import PIL.Image as Image
from PIL import ImageFile, Image
import io
import base64
import numpy as np
import pickle
import uuid


date_string = datetime.datetime.now().strftime("%Y-%m-%d-%H:%M")

port = 9999
s = socket(AF_INET, SOCK_STREAM)
s.bind(('', port))
s.listen(1)

while True:
    conn, addr = s.accept()
    img_dir = '/home/Desktop/frames_saved/'
    img_format = '.png'
    try:
        print("Connected by the ",addr)
        #date_string = datetime.datetime.now().strftime("%Y-%m-%d-%H:%M")
        filename = str(uuid.uuid4())
        with open(img_dir+filename+img_format, 'wb') as file:
            while True:
                data = conn.recv(1024*8)
                if data:
                    print(data)
                    try:
                        file.write(data)
                    except:
                        s = socket(AF_INET, SOCK_STREAM)
                        s.bind(('', port))
                        s.listen(1)
                        conn.sendall(("Hello World"))
                        

                    
                else:
                    print("no data")
    
                    break
    finally:
        conn.close() 

What I am trying to do is receive the encoded string in my android client and print/show a toast.

Android client code:

public class SendImageClient extends AsyncTask<byte[], Void, Void> {

    @Override
    protected Void doInBackground(byte[]... voids) {
        isSocketOpen = true;
        try {
            Socket socket = new Socket("192.168.0.14",9999);
            OutputStream out=socket.getOutputStream();
            DataOutputStream dataOutputStream = new DataOutputStream(out);
            BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            StringBuilder response = new StringBuilder();
            String line;

            while (isSocketOpen){
                Log.d("IMAGETRACK", "Wrote to the socket[1]");
                dataOutputStream.write(voids[0],0,voids[0].length);
                out.close();
                Log.d("IMAGETRACK2", "Wrote to the socket[2]");
                while ((line = input.readLine()) != null)
                    Log.d("IMAGETRACK3", "Wrote to the socket[3]");
                    response.append(line);
                Message clientmessage = Message.obtain();
                clientmessage.obj = response.toString();
                Log.d("[MESSAGE]", String.valueOf(clientmessage));
                if(isSocketOpen == false){
                    socket.close();
                    input.close();
                    Log.d("CLOSED", "CLOSED CONNECTION");
                    break;
                }
            }




        } catch (IOException e) {
            e.printStackTrace();
        }


        return null;
    }
}

I am not experienced with streams in Java. The problem with my code is that the string is apparently sent, but is not received by the android client even though i can always send a new image as the server is still running. How can I receive a string from a python server after the image is sent?

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