I'm unable to connect to Azure IoT Hub using the umqtt.robust library with SSL using MicroPython v1.22.2. No explicit error message is provided by the connect method, making it difficult to diagnose the issue further (it fails when wrapping the socket:self.sock = ussl.wrap_socket(self.sock_raw, **self.ssl_params))

from umqtt.robust import MQTTClient

HUB_HOSTNAME = "AzureIoTHubHostName"
PORT = 8883
CLIENT_ID = "DeviceId"
USERNAME = f"{HUB_HOSTNAME}/{CLIENT_ID}/?api-version=2021-04-12"
PASSWORD = "SASToken"
TOPIC = f"devices/{CLIENT_ID}/messages/events/"
MESSAGE = b"Hello Azure IoT Hub!"
CADATA_PATH = "cadata_path"

with open(CADATA_PATH, "rb") as f:
    cadata = f.read()

ssl_params = {"cert_reqs": ussl.CERT_NONE, "cadata": cadata}

client = MQTTClient(
    CLIENT_ID,
    HUB_HOSTNAME,
    port=PORT,
    user=USERNAME,
    password=PASSWORD,
    ssl=True,
    ssl_params=ssl_params,
)

client.connect()

client.publish(TOPIC, MESSAGE)

client.disconnect()

I have tested my certificate file with openssl to check if the handshake occurs (openssl s_client -connect), and it works ok.

Could anyone advise on how to resolve this connectivity issue with Azure IoT Hub using MicroPython? Any guidance would be greatly appreciated.