HTTPClient getting error refused to node JS server (weird behaviour)

Question

Problem: For the first-minute ~ of running the ESP32 script the post request produces HTTPC_ERROR_CONNECTION_REFUSED and therefore no data gets to the server. After the first minute, a few requests get lost but for the most part requests reach the server every 2s~ (as it should).

Function to send data to the server:

void sendPostData(String data) {
  // Send the post data to the server
  http.begin(SERVER_IP);  // Begin the HTTP connection
  http.addHeader("Content-Type", "application/x-www-form-urlencoded");
  int httpResponseCode = http.POST("val=" + data);
  http.writeToStream(&Serial);
  http.end();
}

Node JS server:

var express = require("express");
var bodyParser = require("body-parser");
var app = express();

app.use(bodyParser.urlencoded({ extended: false }));

app.post('/', function (req, res) {
    console.log(req.body);
    res.end();
});

app.listen(80);

If I use a test website to receive POST requests that isn't my server, eg, requestcatcher.com then no requests are lost. And vice versa, if I use a website to send POST requests such as hurl.eu then my server doesn't have any issues.

This is the post request the ESP32 is sending out:

POST / HTTP/1.0
Host: sadasdasd.requestcatcher.com
Connection: close
Accept-Encoding: identity;q=1,chunked;q=0.1,*;q=0
Connection: close
Content-Length: 10
Content-Type: application/x-www-form-urlencoded
User-Agent: ESP32HTTPClient

Answer 1

Try to send data with JSON, You can use ArduinoJson Library for it.

then use code like this in the loop() method.

  StaticJsonBuffer<300> JSONbuffer;   //Declaring static JSON buffer
  JsonObject& JSONencoder = JSONbuffer.createObject();

  JSONencoder["val"] = data;
  char JSONmessageBuffer[300];
  JSONencoder.prettyPrintTo(JSONmessageBuffer, sizeof(JSONmessageBuffer));


  HTTPClient http;    //Declare object of class HTTPClient

  http.begin(SERVER_IP);      //Specify request destination
  http.addHeader("Content-Type", "application/json");  //Specify content-type header

  int httpCode = http.POST(JSONmessageBuffer);   //Send the request
  String payload = http.getString();

  http.end(); 
  delay(1000);