问nodemcu无法连接到MQTT云服务器，代码如下（必须疑问号结尾手动狗头）？

#include <ESP8266WiFi.h>

#include <PubSubClient.h>

#include "DHT.h"

#define DHTPIN D4 // what pin we're connected to

#define wifi_ssid "TP-LINK_A051"

#define wifi_password "19730908"

#define CLIENT_ID "OFUPTQ0E0Dwechat"

#define MQTT_USRNAME "OFUPTQ0E0Dwechat;12010126;ZZD4M;1620016479"

#define MQTT_PASSWD "8201b39d2bee4244ac369e4f8d7639cc54e3f6d298ece9c492725dd96cfeb3d9;hmacsha256"

#define mqtt_server "OFUPTQ0E0D.iotcloud.tencentdevices.com" // MQTT Cloud address

#define humidity_topic "OFUPTQ0E0D/wechat/humidity"

#define temperature_topic "OFUPTQ0E0D/wechat/temperature"

#define DHTTYPE DHT11 // DHT 11

WiFiClient espClient;

PubSubClient client(espClient);

DHT dht(DHTPIN, DHTTYPE);

void setup() {

Serial.begin(9600);

setup_wifi();

client.setServer(mqtt_server,1883);

dht.begin();

}

void setup_wifi() {

delay(10);

WiFi.begin(wifi_ssid, wifi_password);

while (WiFi.status() != WL_CONNECTED) {

delay(500);

Serial.print(".");

}

}

void reconnect() {

// Loop until we're reconnected

while (!client.connected()) {

Serial.print("Attempting MQTT connection...");

if (client.connect("CLIENT_ID, MQTT_USRNAME, MQTT_PASSWD")) {

Serial.println("connected");

} else {

Serial.print("failed, rc=");

Serial.print(client.state());

Serial.println(" try again in 5 seconds");

delay(5000);

}

}

}

bool checkBound(float newValue, float prevValue, float maxDiff) {

return newValue < prevValue - maxDiff || newValue > prevValue + maxDiff;

}

long lastMsg = 0;

float temp = 0.0;

float hum = 0.0;

float diff = 1.0;

void loop() {

if (!client.connected()) {

reconnect();

}

client.loop();

long now = millis();

if (now - lastMsg > 30000) {

// Wait a few seconds between measurements

lastMsg = now;

float newTemp = dht.readTemperature();

float newHum = dht.readHumidity();

if (checkBound(newTemp, temp, diff)) {

temp = newTemp;

Serial.print("New temperature:");

Serial.println(String(temp).c_str());

client.publish(temperature_topic, String(temp).c_str(), true);

}

if (checkBound(newHum, hum, diff)) {

hum = newHum;

Serial.print("New humidity:");

Serial.println(String(hum).c_str());

client.publish(humidity_topic, String(hum).c_str(), true);

}

}

}