# Join-request to cluster-local Join Server failed DevNonce has already been used in registered node **URL:** \ **Category:** End Devices (Nodes)\ **Created:** [October 14, 2021, 9:27am UTC](https://www.thethingsnetwork.org/forum/t/join-request-to-cluster-local-join-server-failed-devnonce-has-already-been-used-in-registered-node/52381 "2021-10-14T09:27:00Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![bertrik](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/bertrik/32/35697_2.png) [@bertrik](https://www.thethingsnetwork.org/forum/u/bertrik)\ **Post date:** [October 14, 2021, 8:44pm UTC](https://www.thethingsnetwork.org/forum/t/join-request-to-cluster-local-join-server-failed-devnonce-has-already-been-used-in-registered-node/52381/2 "2021-10-14T20:44:52Z")
Maybe your water meters have a firmware that performs a join on every data upload (that is bad behaviour). On every join a “nonce” is used, basically a unique number. Your device cannot use the same nonce twice, and at some point you run out of unique numbers (it’s a 16-bit counter I think). With newer versions of the LoRaWAN specification, the nonce should be incrementing (not just some random unique number). See also: > [@LoRaWAN 1.1 devNonce must be stored in a non-volatile memory on end device](https://www.thethingsnetwork.org/forum/t/lorawan-1-1-devnonce-must-be-stored-in-a-non-volatile-memory-on-end-device/48995): > > According to the LoRaWAN 1.1 specification, the end device generates the DevNonce which is a 2-byte counter, starting at 0 when the device is initially powered up and incremented with every join-request. The DevNonce value is used to prevent replay attacks. This means a DevNonce value will never be reused and therefore an end-device must store the DevNonce in a non-volatile memory. Question: Must an end device supporting LoRaWAN 1.1 have a non-volatile memory to store the DevNonce? Note: Unf… --- _[View the full topic](https://www.thethingsnetwork.org/forum/t/join-request-to-cluster-local-join-server-failed-devnonce-has-already-been-used-in-registered-node/52381)._