RE: nrf9160 connection to azure iot hub: Cloud MQTT input error: -128

Reimer — Fri, 29 Sep 2023 06:43:14 GMT

To who this might concern,

Solved the issue in this post: https://devzone.nordicsemi.com/f/nordic-q-a/99066/nrf9160dk-mqtt-connection-error---azure-iot-hub/448036

Kind regards,

Reimer

RE: nrf9160 connection to azure iot hub: Cloud MQTT input error: -128

Reimer — Tue, 26 Sep 2023 07:00:31 GMT

Hi Didrik

Thanks for the answer!

I'm currently shouldn't be sending anything C2D.

Here is the modem trace:

devzone.nordicsemi.com/.../trace_2D00_2023_2D00_09_2D00_26T07_2D00_02_2D00_11.324Z.mtrace

Kind regards,

Reimer

RE: nrf9160 connection to azure iot hub: Cloud MQTT input error: -128

Didrik Rokhaug — Mon, 25 Sep 2023 12:33:04 GMT

Hi,

It looks like you are able to connect to Azure, and that the connection first fails when you start sending data:

[0m[00:00:04.053,680] [0m<inf> azure_iot_hub_sample: AZURE_IOT_HUB_EVT_CONNECTING
[0m[00:00:14.089,324] [0m<inf> azure_iot_hub_sample: Connection request sent to IoT Hub
[0m+CSCON: 0[00:00:20.514,465] [0m<inf> azure_iot_hub_sample: RRC mode: Idle
[0m+CSCON: 1[00:00:37.516,296] [0m<inf> azure_iot_hub_sample: RRC mode: Connected
[0m[00:00:37.692,443] [0m<inf> azure_iot_hub_sample: AZURE_IOT_HUB_EVT_CONNECTED
[0m[00:00:37.799,560] [0m<inf> azure_iot_hub_sample: AZURE_IOT_HUB_EVT_READY
[0m[00:00:37.799,896] [0m<inf> azure_iot_hub_sample: Sending event:{"temperature":25.9,"timestamp":37799}
[0m[00:00:37.801,422] [0m<inf> azure_iot_hub_sample: Event was successfully sent
[0m[00:00:37.801,422] [0m<inf> azure_iot_hub_sample: Next event will be sent in 20 seconds
[0m[00:00:37.944,366] [1;33m<wrn> azure_iot_hub: DISCONNECT, result: -128
[0m[00:00:37.944,366] [0m<inf> azure_iot_hub_sample: AZURE_IOT_HUB_EVT_DISCONNECTED

Are you sending anything from Azure to the device?

The modem's TLS buffer is only 2kB, so if a TLS fragment is larger than that, it cannot be decoded by the modem, and the connection will be closed.

Anyway, when debugging these kind of issues, a modem trace is very helpful, as it lets us see the communication between the device and the cloud.

Best regards,

Didrik