# WSREP: cluster conflict due to certification failure

**URL:** <https://forums.percona.com/t/wsrep-cluster-conflict-due-to-certification-failure/8218>\
**Category:** Percona Server for MySQL 5.7\
**Tags:** mysql, percona\
**Created:** [October 31, 2020, 6:07pm UTC](https://forums.percona.com/t/wsrep-cluster-conflict-due-to-certification-failure/8218 "2020-10-31T18:07:32Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![przemek](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/przemek/32/3_2.png) [@przemek](https://forums.percona.com/u/przemek)\
**Post date:** [November 23, 2020, 9:37am UTC](https://forums.percona.com/t/wsrep-cluster-conflict-due-to-certification-failure/8218/2 "2020-11-23T09:37:45Z")

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Hi,

What if you try using this variable on all nodes:

wsrep\_certification\_rules=‘OPTIMIZED’

That should help for such issues related to tables having FK constraints.

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