# OTAA shows "Activation DevNonce not valid: already used"

**URL:** <https://www.thethingsnetwork.org/forum/t/otaa-shows-activation-devnonce-not-valid-already-used/5079>\
**Category:** v2 Backend\
**Created:** [January 25, 2017, 2:45am UTC](https://www.thethingsnetwork.org/forum/t/otaa-shows-activation-devnonce-not-valid-already-used/5079 "2017-01-25T02:45:13Z")\
**Posts on this page:** 1\
**Showing post:** 13

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**Author:** ![arjanvanb](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/arjanvanb/32/46626_2.png) [@arjanvanb](https://www.thethingsnetwork.org/forum/u/arjanvanb)\
**Post date:** [February 28, 2017, 6:58pm UTC](https://www.thethingsnetwork.org/forum/t/otaa-shows-activation-devnonce-not-valid-already-used/5079/13 "2017-02-28T18:58:27Z")

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A workaround from @htdvisser on Slack, if you really need to clear the nonces that TTN has stored:

> The backend clears the DevNonces when you change the AppKey, so if this is a problem, you can just change the AppKey to something else and then change it back

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