esp-32 post to thingspeak

#include <OneWire.h>
#include <DallasTemperature.h>
#include <WiFi.h>                  //already included in esp32 package
#include "DHT.h"

#define DHTPIN 32
#define oneWireBus  33
#define DHTTYPE DHT22
#define moistPin  35
#define LDRPin  34
DHT dht(DHTPIN, DHTTYPE);
OneWire oneWire(oneWireBus);
DallasTemperature sensors(&oneWire);
String apiKey = "BE7U15RJYY57AV91";                  //  Enter your Write API key from ThingSpeak
const char *ssid =  "SSID";                                    // replace with your wifi ssid and wpa2 key
const char *pass =  "PASSWORD";
const char* server = "api.thingspeak.com";           //don't change
float soilTemperature, h, t, lightIntensity, soilMoisture;
WiFiClient client;
void setup()
{
  Serial.begin(115200);
  delay(10);
  Serial.begin(115200);
  sensors.begin();  //starts ds18b20
  dht.begin();   //give 2 second delay to all sensors
  Serial.println("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");

}
void loop()
{
  if (client.connect(server, 80))                                //   "184.106.153.149" or api.thingspeak.com
  {

    String postStr = apiKey;                          //keep the apikey variable unchanged just add fields and values
    postStr += "&field1=";
    postStr += String(h);
    postStr += "&field2=";
    postStr += String(t);
    postStr += "&field3=";
    postStr += String(soilTemperature);
    postStr += "&field4=";
    postStr += String(lightIntensity);
    postStr += "&field5=";
    postStr += String(soilMoisture);
    postStr += "\r\n\r\n";

    client.print("POST /update HTTP/1.1\n");               //keep this part unchanged
    client.print("Host: api.thingspeak.com\n");
    client.print("Connection: close\n");
    client.print("X-THINGSPEAKAPIKEY: " + apiKey + "\n");
    client.print("Content-Type: application/x-www-form-urlencoded\n");
    client.print("Content-Length: ");
    client.print(postStr.length());
    client.print("\n\n");
    client.print(postStr);
    client.stop();
    Serial.println("Waiting...");
    delay(30000);                                      //the website accepts values in 30 seconds so we add a delay of 30 seconds before loop restarts
    getSensorValues();
  }
}


  void getSensorValues() {
    sensors.requestTemperatures();
    float soilTemp = sensors.getTempCByIndex(0);
    float h = dht.readHumidity();
    t = dht.readTemperature();
    if (isnan(h) || isnan(t)) {
      Serial.println(F("Failed to read from DHT sensor!")); //print to server
      return;
    }
    lightIntensity = analogRead(LDRPin); // read the value from the LDR
    soilMoisture = analogRead(moistPin);
  }