cannot connect to aws iot using umqtt.simple

Comienza con simple1.py en la línea 92, en connect, y con la salida de depuración que muestra una respuesta vacía después de enviar los bytes de MQTT. Reproduce el intento de conexión con la configuración de AWS IoT proporcionada y, a continuación, sigue el procesamiento de la respuesta para identificar el fallo. Se considera terminado cuando se haya confirmado la causa y se haya demostrado una conexión exitosa, o se haya documentado la configuración necesaria.

My code

import time
import machine
import network
import ujson
from simple1 import MQTTClient

SSID = b'Exxxye'
PASS = b'8xxx766'
CLIENT_ID = b'ixxxxxxxxxxxx6eb63'
AWS_ENDPOINT = b'xxxxx-1.amazonaws.com'

PUB_TOPIC = b'temperature'
SUB_TOPIC = b'temperature'
with open('/pri.der', 'rb') as f:
    DEV_KEY = f.read()

with open('/cert.der', 'rb') as f:
    DEV_CRT = f.read()

light = machine.Pin("LED", machine.Pin.OUT)
light.off()


def wifi_connect():
    print('Connecting to wifi...')
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    wlan.connect(SSID, PASS)
    while wlan.isconnected() == False:
        light.on()
        print('Waiting for connection...')
        time.sleep(0.5)
        light.off()
        time.sleep(0.5)
    print('Connection details: %s' % str(wlan.ifconfig()))

def mqtt_subscribe_callback(topic, msg):
    print("Received topic: %s message: %s" % (topic, msg))
    if topic == SUB_TOPIC:
        mesg = ujson.loads(msg)
        if 'state' in mesg.keys():
            if mesg['state'] == 'on' or mesg['state'] == 'ON' or mesg['state'] == 'On':
                light.on()
                print('Light is ON')
            else:
                light.off()
                print('Light is OFF')

def get_rpi_temperature():
    sensor = machine.ADC(4)
    voltage = sensor.read_u16() * (3.3 / 65535)
    temperature = 27 - (voltage - 0.706) / 0.001721
    return temperature


wifi_connect()


mqtt = MQTTClient(
    client_id=CLIENT_ID,
    server=AWS_ENDPOINT,
    port=8883,
    keepalive=120,
    ssl=True,
    ssl_params={'key':DEV_KEY, 'cert':DEV_CRT, 'server_side':False})

mqtt.connect()

mqtt.set_callback(mqtt_subscribe_callback)


mqtt.subscribe(SUB_TOPIC)

while True:
message = b'{"temperature":%s, "temperature_unit":"Degrees Celsius"}' % get_rpi_temperature()
    print('Publishing topic %s message %s' % (PUB_TOPIC, message))

    mqtt.publish(topic=PUB_TOPIC, msg=message, qos=1)

    # Check subscriptions for message
    mqtt.check_msg()
    time.sleep(5)

My error code:

Connecting to wifi...
Connection details: ('192.168.x.xx', '255.255.255.0', '192.168.xx.xx', '192.168.xx.xx')
dbug-msg: 0x9 b'04:4d:51:54:54:04:02:00:78'
dbug-resp: b''
Traceback (most recent call last):
File "", line 81, in
File "simple1.py", line 92, in connect
IndexError: bytes index out of range

please someone help me on this..i tried everything