Unable to register device: unknown server response error when registering device using Azure Functions

Tiaan Smit 31

We currently make use of the IoT Central device bridge solution detailed in https://learn.microsoft.com/en-us/azure/iot-central/core/howto-build-iotc-device-bridge to connect devices to IoT Central.

Within the Azure Function App we have multiple Functions running for different data processing requirements, depending on the device, before entering the telemetry into IoT Central. A single device's telemetry usually gets transferred to IoT Central on a 15 min interval.

This has been working well enough, though recently we have been occasionally receiving an 'Unable to register device: unknown server response' error while the Function registers the device with the IoT Central's DPS. I cannot find a clear reason as to why this would only sometimes happen and not on every attempt.

I also have not been able to find possible reasons for this specific error from the DPS.
Does anyone know what my issue could be? Any assistance would be appreciated.

Sander van de Velde 28,546 Reputation points MVP

2023-08-29T11:23:48.9966667+00:00

Which Region are you using?
Tiaan Smit 31 Reputation points

2023-08-30T06:12:24.13+00:00

Hi Sander

All of the above-mentioned resources are in the West Europe region.
LeelaRajeshSayana-MSFT 13,461 Reputation points

2023-09-01T20:06:39.02+00:00

Hi @Tiaan Smit Thank you for sharing the details. May I also know if you have made any modifications to the code or using the same sample provided in the URL Engine.js to register the device? Did you get a chance to inspect the notice any other events such as device telemetry failure errors around the time you notice this error? Since this issue appears to be intermittent, without additional details, it is hard to determine the root cause. Please let us know if there are any additional logs/stack traces you can share with to better understand the issue.
Tiaan Smit 31 Reputation points

2023-09-07T11:11:14.7166667+00:00

Hi Leela

We are making use of the sample provided as part of the device bridge, though we have not made any mods to the code. The goal was to make it a generic solution that can be easily replicated, hence why we went with the device bridge, and we try to avoid making changes to a working part of the solution.
There were no other errors as far as I could tell around that time. The whole function seemed to execute as per usual up until it tries to get the device hub.

Here is the exact exception that is thrown:

Result: Failure Exception: Unable to register device 6E28005265: Unknown server response Stack: Error: Unable to register device 6E28005265: Unknown server response at getDeviceHub (C:\home\site\wwwroot\DSE930IoTHubBridge\lib\engine.js:156:15) at process.processTicksAndRejections (node:internal/process/task_queues:95:5) at async getDeviceConnectionString (C:\home\site\wwwroot\DSE930IoTHubBridge\lib\engine.js:88:33) at async module.exports (C:\home\site\wwwroot\DSE930IoTHubBridge\lib\engine.js:45:55) at async module.exports (C:\home\site\wwwroot\DSE930IoTHubBridge\index.js:252:13)

I am not sure if I am able to get more information, but please ask if there is anything that might help resolve the issue.
LeelaRajeshSayana-MSFT 13,461 Reputation points

2023-09-11T21:36:48.31+00:00

Hi @Tiaan Smit For a deeper investigation and immediate assistance on this issue, please file a support request @ https://aka.ms/azsupt? If you do not have access to a support plan, could you please send an email with the below details, so that we can work closely on this matter.

Thread URL: Link to this thread.

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Email Subject : Attn Leela