ThingSpeak Using MQTT Blocks with Jetson Nano n External Mode, Data neither publish nor reflected

MQTT Message from Jetson Nano not published in MQTT using Simulink External Mode.

Here are the details:

Environment:

Target: Jetson Nano 4GB Developer Kit B01

Matlab (Simulink) Version: Academic/2025b

Simulink Example in use: Publish and Subscribe to Messages on ThingSpeak Using MQTT Blocks

Build Status: Successful

Publish Topic: channels/3122381/publish/fields/field1

Could you please help in?

Thanks

Beda

[Vinod]

Please create a technical support request to tech support can gather more information and help you.

[Christopher Stapels]

Are you able to publish from a desktop MQTT client?

[Neeraj]

By following the example https://in.mathworks.com/help/coder/nvidia/ug/publish-subscribe-mqtt-nvidia-jetson.html I was able to publish and subscibe MQTT messages to Thingspeak from Nvidia Jetson AGX Orin using Simulink external mode (Communication interface: XCP on TCP/IP ).

If the message payload is of type 'uint8', then the chart for the respective field of the Channel will not update as it would interpret the data as a non-printable character(ASCII), because of which it may appear that the MQTT blocks are not working.

But the number of entries are getting updated and also when trying to export the data as JSON I am able to see the published data.

I have used the port 1883 for which there is no encryption.