how to i recive post request from mit appinventor to ESP8266?

im trying to send some text using mit appinventor to my esp8266 so it will print it to serial using some example i find online it works with postman but with mit appinventor it shows nothing any help?
this is my code

 #include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
ESP8266WebServer server(80);
const char* ssid = "****";
const char* password =  "*******";
void setup() {
    WiFi.begin(ssid, password);  //Connect to the WiFi network
    while (WiFi.status() != WL_CONNECTED) {  //Wait for connection
        Serial.println("Waiting to connect...");
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());  //Print the local IP
    server.on("/body", handleBody); //Associate the handler function to the path
    server.begin(); //Start the server
    Serial.println("Server listening");
void loop() {
    (); //Handling of incoming requests
void handleBody() { //Handler for the body path
      if (server.hasArg("plain")== false){ //Check if body received
            server.send(200, "text/plain", "Body not received");
      String message = "Body received:\n";
             message += server.arg("plain");
             message += "\n";
      server.send(200, "text/plain", message);

this is my blocks

it works with post man

this is the serial output when im using postman

Body received:
    (); //Handling of incoming requests

How? You are not calling a named function to handle requests. I can't believe that works regardless of which external app is making the request.

Where is that anonymous function defined?