IoT GetStream request rejected for out of the range of data available.

Question

Hi, I am new to IoT Core, and I am implementing MQTT-based file delivery. I created stream for the file located at S3 bucket. When I publish the request message using client to the topic `$aws/things/mydevice/streams/stream12345/get/json`, it publish a reject message in topic `$aws/things/mydevice/streams/stream12345/rejected/json`: 
```
 {
  "code": "InvalidRequest",
  "o": "InvalidRequest",
  "message": "The data requested is out of the range of data available.",
  "m": "The data requested is out of the range of data available."
}
```
I have made sure that:
1. My device environment can access such file in S3 ( I used `curl ` and it displayed content`
2. The stream has an role that has full IoT and S3 permissions (I know it's not recommended, but for testing, I enabled them both but still doesn't work)

Now then, I don't understand why it's out of reach. There are no questions in the forum and online, so I asked this for more info and guidance. I don't think [documentation](https://docs.aws.amazon.com/iot/latest/developerguide/mqtt-based-file-delivery-in-devices.html) explain this well (in beginner's perspective)

Thank you for the help in advance!!!

Accepted Answer

Hi. `InvalidRequest` is [defined in the documentation](https://docs.aws.amazon.com/iot/latest/developerguide/mqtt-based-file-delivery-in-devices.html#mqtt-based-file-delivery-errors) as:

> The request is generally identified as malformed. For more information, see the error message.

So it seems likely the payload you sent in the `get` is incorrect. Please review that: https://docs.aws.amazon.com/iot/latest/developerguide/mqtt-based-file-delivery-in-devices.html#mqtt-based-file-delivery-get-getstream

The [AWS IoT Device SDK for Embedded C](https://github.com/aws/aws-iot-device-sdk-embedded-C) includes an [OTA library](https://github.com/aws/ota-for-aws-iot-embedded-sdk) that has an implementation of MQTT file streaming. It may be useful to review how it constructs a GetStream request: https://github.com/aws/ota-for-aws-iot-embedded-sdk/blob/main/source/ota_cbor.c#L238

If you are developing this in C for a device firmware update, I recommend you instead use the AWS IoT C SDK libraries.

IoT GetStream request rejected for out of the range of data available.

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