fail to load CA certificate

[kohenro19]

I am trying to connect Raspberry Pi Pico W(MicroPython v1.23.0) to Azure Iot Hub but cannot make it.
As the error blow shown, I fail to load the CA certicate

Traceback (most recent call last):
  File "<stdin>", line 16, in <module>
  File "ssl.py", line 1, in load_verify_locations
ValueError: invalid cert

Would you share the sample code to load CA certificate of the latest version of ssl.py ?

This is the source code which happen the error.

import machine
from umqtt.simple import MQTTClient
# from simple import MQTTClient
from machine import Pin
import connect_to_wifi
import ssl

if __name__ == "__main__":
    connect_to_wifi.connect()  
    hostname = <HOSTNAME>
    clientid = <CLIENTID>
    passw = <SAS TOKEN>
    username = <HOSTNAME>/<CLIENTID>/?api-version=2021-04-12"
    
    ssl = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
    ssl.load_verify_locations(cafile="DigiCertGlobalRootG2.crt.pem")
    client = MQTTClient(client_id=clientid, server=hostname, port=0, keepalive=60, password=passw, ssl=ssl)        
    client.connect()
    print('Connected to IoT Hub MQTT Broker')

I downloaded CA certificate from https://cacerts.digicert.com/DigiCertGlobalRootG2.crt.pem
the .py file and the CA certificate are in a same directory.

[kohenro19]

as converting CA certificate form .pem to .der, the error became like this

Traceback (most recent call last):
  File "<stdin>", line 18, in <module>
  File "umqtt/simple.py", line 106, in connect
MQTTException: 5

This means that the authentication fail ?

[scruss]

Have you set the RTC on the Raspberry Pi Pico W to the correct time using something like ntptime.settime()?

[kohenro19]

Thank you so much for giving me the advice.

Although I added the function to sync ntp like this, the error is still same

def sync_time():
    try:
        print('Synchronizing time...')
        ntptime.settime()
        print('Time synchronized!')
        
        # UTC時刻を取得
        utc_time = utime.time()
        
        # JSTに補正
        jst_time = utc_time + JST_OFFSET
        jst_tuple = utime.localtime(jst_time)
        
        print('Current JST time:', jst_tuple)
    except Exception as e:
        print('Failed to synchronize time:', e)
        
if __name__ == "__main__":
    connect_to_wifi.connect()  
    sync_time()
~

MPY: soft reboot
Connected!
IP Address: 192.168.202.72
Netmask: 255.255.255.0
Default Gateway: 192.168.202.198
Name Server: 192.168.202.198
Synchronizing time...
Time synchronized!
Current JST time: (2024, 7, 7, 16, 28, 57, 6, 189)
Traceback (most recent call last):
  File "<stdin>", line 43, in <module>
  File "umqtt/simple.py", line 106, in connect
MQTTException: 5

[kohenro19]

As soon as I generated SAS token by vscode, I tried to connect pico to azure iot, but got the same error code(5)