# Error in the database logs: WSREP: unserialize error invalid protocol version 3

**URL:** <https://forums.percona.com/t/error-in-the-database-logs-wsrep-unserialize-error-invalid-protocol-version-3/7960>\
**Category:** Percona XtraDB Cluster 5.x\
**Created:** [August 27, 2020, 7:31am UTC](https://forums.percona.com/t/error-in-the-database-logs-wsrep-unserialize-error-invalid-protocol-version-3/7960 "2020-08-27T07:31:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![DRON4eg](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/dron4eg/32/1380_2.png) [@DRON4eg](https://forums.percona.com/u/DRON4eg)\
**Post date:** [August 27, 2020, 7:31am UTC](https://forums.percona.com/t/error-in-the-database-logs-wsrep-unserialize-error-invalid-protocol-version-3/7960/1 "2020-08-27T07:31:18Z")

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Good afternoon, please tell me in the logs of one server (a cluster of 3 nodes) Varning-Error periodically appears:

```auto
2020-08-27T10:55:50.536154Z 0 [Warning] WSREP: unserialize error invalid protocol version 3: 71 (Protocol error)
at gcomm/src/gcomm/datagram.hpp:unserialize():135

```

With what it can be connected? What can be done to fix this?

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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, 9:29am UTC](https://forums.percona.com/t/error-in-the-database-logs-wsrep-unserialize-error-invalid-protocol-version-3/7960/2 "2020-11-23T09:29:14Z")

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Hello,

That message usually appears when something external is probing the TCP port used by Galera (4567 by default) communication.

You can try out to reproduce it by telneting the port or scan it with nmap or similar.

If all cluster nodes run with same version of Galera plugin, that is unlikely to happen due to any legitimate cluster activity.