Devnonce error same network one gateway work another doesn't

Hi everyone,
I don’t understand why with 2 gateways up and connected to the same network, one gateway works with all the devices but the other one doesn’t work with any of those devices, reply is devnonce error for the devices.

Where to start with troubleshooting on that gateway? Gateway used to work in the past with the same devices

Thank you,

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Can you help me?
One gateway is not working but it used to work. Under that gateway I have all the devices with “devnonce error”, but the orher gayeways work well

Thank yoy,

Could this be related to network latency difference between the two gateways? Please note that if one packet arrives late (e.g. to high network latency), the de-duplication process has already been completed and thus the device has already been activated.

Then when the late packet comes in, ChirpStack detects that that nonce has already been used and you get the error that you mentioned.

If it is not related to the de-duplication process, then the issue is not with the gateway. The gateway doesn’t do anything with these nonces. Maybe the device is re-using the nonces?