See rejected lorawan uplinks

Question

Hi,

I am migrating my solution for IoTCore. I am having trouble with some devices that stopped to transmit, but in Gateway I can see this device transmitting. Somebody can help to solve it? Or is there way to see rejected uplinks or data traffic from Gateway ? 
In addition, before I used Chirpstack at EC2 and worked. I also used TTN to validate the incoming packages and I can see all devices communicating on Gateway data traffic.

My setup:
I am using AU915-1 DR4 to transmit packages, ABP mode, Lorawan 1.0.3 and payload has 46 bytes. 
There are 24 devices registered on IotCore. Only 21 communicating. Each device sends confirmed uplink every 10 seconds.
There are 16 devices communicating with Dragino LPS8
There are 8 devices communicating with Dragino DLOS8.

Greg_B · Answer

Hi. Do the misbehaving devices ever get any uplinks received in AWS IoT Core for LoRaWAN? If not, then I would suspect the device has been provisioned in AWS IoT Core with incorrect DevEUI, NwkSKey, etc.

How are you monitoring the arrival of uplinks in AWS IoT Core? If you haven't already, please use [Network Analyzer](https://docs.aws.amazon.com/iot/latest/developerguide/connect-iot-lorawan-network-analyzer-overview.html) to check whether the uplinks reach AWS IoT Core for LoRaWAN and whether it tries to send confirmations or not. Video: https://www.youtube.com/watch?v=Qk9pkhL8xjc

I also recommend you enable AWS IoT Wireless logging, if you haven't already, so you can use CloudWatch for your debugging: https://docs.aws.amazon.com/iot/latest/developerguide/connect-iot-lorawan-configure-logging.html

Joao Paulo · Answer

Hi Greg,
Thanks for the answer. 
Yes, They did, but after some time they stop work.

I'm using CloudWatch to log, but I can see only valids uplink and I also tried to use Network Analyzer but it shows nothing of offline (in IoT Core) device. In case of invalid MIC, is it shown somewhere?

I did some tests and devices go to offline after packet with FCnt between 65541 and 65543.
On my gateway I can see FCnt going to 00 after 65535

See rejected lorawan uplinks

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