been trying to figure out a code for an ESP32 to send a POST API every 10seconds.
The code sucessfully connects to the Wifi and receive status 200 for every POST it does on the first connection. However, if I force the wifi off and turn it on again sometimes I receive a “HTTPClient initialized, Error code: -1” everytime, and then cannot make it work again.
Only method to make it work again is if I reupload the code to the ESP. Then it reconnects again and succeeds on the API calls.

*Important to say that at some reconnections it works also, but at some they get bugged with no return.

Code im using:

#include <ArduinoJson.h>
#include <WiFi.h>
#include <HTTPClient.h>
#include <base64.h>

const char* ssid = "ssid";
const char* password = "pass";
const char* url = "https://url";
const char* stringconn = "user:password";

unsigned long lastRequestTime = 0;
const unsigned long requestInterval = 10000; // 10 seconds
const unsigned long maxBackoffInterval = 600000; // 10 minutes
unsigned long lastWifiCheckTime = 0;
unsigned long backoffInterval = 1000; // Initial backoff interval
const int maxConnectionAttempts = 5; // Maximum connection attempts

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

void loop() {
  unsigned long currentTime = millis();

  if (currentTime - lastWifiCheckTime >= backoffInterval) {
    lastWifiCheckTime = currentTime;
    if (WiFi.status() != WL_CONNECTED) {
      Serial.println("WiFi disconnected, attempting to reconnect...");
      connectToWiFi();
    }
  }

  if (currentTime - lastRequestTime >= requestInterval) {
    sendPostRequest();
    lastRequestTime = currentTime;
  }
}

void connectToWiFi() {
  Serial.print("Connecting to WiFi...");
  WiFi.begin(ssid, password);
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < maxConnectionAttempts) {
    delay(500);
    Serial.print(".");
    attempts++;
  }
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("Connected!");
    // Reset backoff interval on successful connection
    backoffInterval = 1000;
  } else {
    Serial.println("Connection failed.");
    // Exponential backoff
    if (backoffInterval < maxBackoffInterval) {
      backoffInterval *= 2;
    }
  }
}

// Function to send POST request
void sendPostRequest() {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http; // Create a new HTTPClient instance
    Serial.println("HTTPClient initialized");

    http.begin(url); // Initialize the HTTP client instance

    // Create JSON data
    StaticJsonDocument<200> jsonDoc;
    jsonDoc["device"] = "ESP_TST";

    String jsonString;
    serializeJson(jsonDoc, jsonString);

    // Set headers
    http.addHeader("Content-Type", "application/json");

    // Set Basic Authentication
    String encodedAuth = base64::encode(stringconn);
    String authHeader = "Basic " + encodedAuth;
    http.addHeader("Authorization", authHeader);

    // Send the request only if connected
    int httpResponseCode = http.POST(jsonString);
    if (httpResponseCode > 0) {
      Serial.print("HTTP Response code: ");
      Serial.println(httpResponseCode);
    } else {
      Serial.print("Error code: ");
      Serial.println(httpResponseCode);
    }

    // Free resources
    http.end();
  } else {
    Serial.println("WiFi not connected, cannot send POST request");
  }
}

Tried several ways of reconnection, didnt work.
also tried chatgpt to seek for a solution: sugested delay, but doesnt seem to be the problem (or resolve the problem).