To connect your IoT device to HiveMQ Cloud broker, you need:
HiveMQ Cloud account and a cluster: https://docs.hivemq.com/hivemq-cloud/quick-start-guide.html
Create a pair of Access Credentials: https://docs.hivemq.com/hivemq-cloud/quick-start-guide.html#create-credentials
The device supporting TLS connections
The device supporting TLS-SNI extension
The device using correct hostname, port and access credentials
The device has the CA certificate: https://letsencrypt.org/certs/isrgrootx1.pem.
How to check if the device supports TLS?
Please refer to the manufacturer documentation for the device.
How to check if the device supports TLS-SNI?
Please refer to the manufacturer documentation for the device.
Alternatively, use a network analysis tool, capture network communication on the MQTT port between the device and the broker, analyse the TLS handshake and find the “Client Hello” packet. If the packet contains the server’s hostname, it indicates that SNI is supported:
If the device is not in the local WiFi you can mock a TLS server locally and expose it globally: How do I test locally if my IoT device has TLS-SNI?
How to check if the hostname, port, and access credentials are correct?
Use a different MQTT client, we suggest MQTT-CLI, and try connecting it using the hostname, port and access credentials.