Thingy 91x aws iot failure

[odik]

trace-2025-10-19T13-19-36.277Z.mtrace

I have succesfully tested my software that sends gnss location to aws iot with nrf9151dk. Recently I configured software also support also thingy91x. My problem is that Aws iot connection drops shortly after connection with following logs:

[00:00:24.660,186] <err> net_mqtt_rx: [CID 0x2001b880]: Connection closed.

[00:00:24.660,247] <inf> net_mqtt_sock_tls: Closing socket 3

[00:00:24.661,132] <dbg> aws_iot: on_disconnect: MQTT client disconnected: result = -128

[00:00:24.661,163] <inf> aws_iot_thread: AWS_IOT_EVT_DISCONNECTED

[00:00:24.661,193] <err> mqtt_helper: Cloud MQTT input error: -128

Certificates should be fine and aws logs show that connection loss is caused by client error. I'm little confused because same code works completly fine with dk but fails with thingy.

[Hakon]

Can you enable AWS IoT lifecycle events to check if the disconnect is caused by a policy issue?

[odik]

They are already enabled and disconnect is casused by "disconnectReason": "CLIENT_ERROR". According to AWS IoT documentation this error is caused by client doing something wrong. However I haven't been able to figure out why is that. Completly identical code works without errors in nRF9151DK but still problem persist only with Thingy.

[Hakon]

What AWS policy are you using?

[odik]

Currrently only iot:Connect and iot:Publish are used. Connection is lost even if nothing else is done after connecting to broker.

[Hakon]

You can try this basic policy;

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "iot:*",
      "Resource": "*"
    }
  ]
}