I get OSError: -2 error when connecting to AliCloud IoT platform as MQTT

[Tethys-Morales]

I tried to connect to the AliCloud IoT platform, via the UMQTT library.
But its throwing OSError: -2 exception.
The detailed problem code is as follows:
Sensitive information has been desensitized

from machine import Pin
import dht
import time
import network
import simple as mqtt
# import _thread
import ujson
ALINK_PROP_SET_METHOD='thing.service.property.set'
led=Pin(2,Pin.OUT,value=0)
state = 0
def threadPublish():
  while True:
    time.sleep(2)
    d.measure()
    print(d.humidity())
    print(d.temperature())
    send_mseg={"params":{"Temperature":d.temperature(),"Humidity":d.humidity()},"method":"thing.service.property.set"}
    client.publish(topic=" ",msg=str(send_mseg),qos=1,retain=False)


def receiveMessage():
  while True:
    client.wait_msg()
#接收信息。接收到的信息是json格式，要进行解析。
def recvMessage(topic,msg):
  parsed=ujson.loads(msg)
  str=parsed["params"]
  print(str)
  print(type(parsed["params"]))
  print(str.get("PowerSwitch"))
  global state
  state=str.get("PowerSwitch")
  if state == 1:
    led.value(1)
    print("led on!") 
  if state == 0:
    led.value(0)
    print("led off!")
   
d=dht.DHT11(Pin(5))
wlan=network.WLAN(network.STA_IF)  
wlan.active(True)
wlan.connect('***','***')#连接WIFI
ProductKey='***'
DeviceName='***'
DeviceSecret='***'
CLIENT_ID='***'
user_name='***'#用户名
user_password='***'#用户密码
SERVER= "***"#阿里云物联网平台地址
PORT=1883
client = mqtt.MQTTClient(client_id=CLIENT_ID, server=SERVER, port=PORT, user=user_name, password=user_password, keepalive=60)
client.connect()
client.set_callback(recvMessage)#设置回调函数
client.subscribe(" ")#订阅主题

while True:
  d.measure()
  print(d.humidity())
  print(d.temperature())
  send_mseg={"params":{"temperature":d.temperature(),"Humidity":d.humidity()},"method":"thing.service.property.set"}
  client.publish(topic=" ",msg=str(send_mseg),qos=1,retain=False)
  time.sleep(2)
_thread.start_new_thread(receiveMessage,())#开启多线程

The exception it throws is as follows:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 52, in <module>
  File "simple.py", line 15, in __init__
OSError: -2

Its complete output code is as follows
Sensitive information has been desensitized

mode : sta(84:f3:eb:3c:12:5a) + softAP(86:f3:eb:3c:12:5a)
#5 ets_task(4020ed80, 28, 3fff9eb0, 10)
add if0
scandone
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 6
cnt 

connected with ***, channel 1
dhcp client start...
ip:192.168.20.17,mask:255.255.255.0,gw:192.168.20.1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 52, in <module>
  File "simple.py", line 15, in __init__
OSError: -2

I did not find any information about this on the Internet.
I hope to know the appropriate solution.

The content of this post has been translated and may not be accurate, sorry for that.