ESP32 Server error 500

[rnlcnls]

tried sending code to my android app but when i press get data, it shows Server Error 500, here is my ESP32 code, also the data shows on the web browser when i type the ip of my ESP32 in chrome

#include <WiFi.h>
#include <ESPAsyncWebServer.h>
#include <ArduinoJson.h>
#include <AsyncTCP.h>

const char* ssid = "ESP32-Access-Point";
const char* password = "YourPassword";

AsyncWebServer server(80);

JsonDocument jsonDoc;

void setup() {
  Serial.begin(115200);

  WiFi.mode(WIFI_AP);
  WiFi.softAP(ssid, password);
  IPAddress IP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(IP);

  // Define routes using on
  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request) {
    handleGetRequest(request);
  });

  server.begin();
}

void handleGetRequest(AsyncWebServerRequest *request) {
  Serial.println("Received GET request");
  jsonDoc["message"] = "Hello from ESP32!";
  String jsonStr;
  serializeJson(jsonDoc, jsonStr);
  Serial.println("Sending JSON response: ");
  Serial.println(jsonStr);
  request->send(200, "application/json", jsonStr.c_str());
}

void loop() {
  // Your code here
}

[gilshultz]

@rnlcnls

Server Error 500,

A 500 Internal Server error means that the website you were trying to connect to has experienced a problem and can't provide a more specific error code.

[rnlcnls]

is the problem on my ESP32 setup code or may be in my android studio code?

public void onClickGetData(View view) {
        new Thread(() -> {
            OkHttpClient client = new OkHttpClient();
            String url = "http://192.168.4.1/json";
            Request request = new Request.Builder()
                    .url(url)
                    .build();
            client.newCall(request).enqueue(new Callback() {
                @Override
                public void onResponse(@NonNull Call call, @NonNull Response response) {
                    if (response.isSuccessful()) {
                        try {
                            assert response.body() != null;
                            SimpleTextMessage message = new Gson().fromJson(response.body().string(), SimpleTextMessage.class);
                            runOnUiThread(() -> {
                                String formattedMessage = getString(R.string.message_format, message.message);
                                tvShowData.setText(formattedMessage);
                            });
                        } catch (Exception e) {
                            handleErrorOnUiThread("Parsing error");
                        }
                    } else {
                        handleErrorOnUiThread("Server error: " + response.code());
                    }
                }

                @Override
                public void onFailure(@NonNull Call call, @NonNull IOException e) {
                    handleErrorOnUiThread("Network error: " + e.getMessage());
                }
            });
        }).start();
    }

    private void handleErrorOnUiThread(String message) {
        new Handler(Looper.getMainLooper()).post(() -> Toast.makeText(MainActivity.this, message, Toast.LENGTH_LONG).show());
    }
    private static class SimpleTextMessage {
        String message;
    }
}

this is my android studio code, used the latest ver of okhttp3 and implemented Gson, i also added the clearTextPermit to true