# Error after migration Elastic "Fleet Server - Error - failed version compatibility check with elasticsearch: x509: certificate signed by unknown authority"

**URL:** <https://discuss.elastic.co/t/error-after-migration-elastic-fleet-server-error-failed-version-compatibility-check-with-elasticsearch-x509-certificate-signed-by-unknown-authority/380288>\
**Category:** Elastic Agent\
**Tags:** fleet\
**Created:** [July 21, 2025, 6:56am UTC](https://discuss.elastic.co/t/error-after-migration-elastic-fleet-server-error-failed-version-compatibility-check-with-elasticsearch-x509-certificate-signed-by-unknown-authority/380288 "2025-07-21T06:56:37Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![Tortoise](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tortoise/32/147587_2.png) [@Tortoise](https://discuss.elastic.co/u/Tortoise)\
**Post date:** [July 21, 2025, 10:10am UTC](https://discuss.elastic.co/t/error-after-migration-elastic-fleet-server-error-failed-version-compatibility-check-with-elasticsearch-x509-certificate-signed-by-unknown-authority/380288/2 "2025-07-21T10:10:52Z")

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Hello @neofall

As per below post maybe once check the fingerprint?

> [@Fleet agent installation failed: x509 error with --insecure](https://discuss.elastic.co/t/fleet-agent-installation-failed-x509-error-with-insecure/366259/5):
>
> Hey! sure thing: When deploying the ES cluster for the first time I had to extract the fingerprint of the http certificate by executing the following command in any of the members of the cluster: openssl x509 -in /usr/share/config/http-certs/ca.crt -sha256 -fingerprint | grep SHA256 | sed 's/://g' The result of this command is the trusted fingerprint that should be configured on the output section of the fleet settings. After a year, Elasticsearch renewed the certificate, changing this finge…

Thanks!!

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_[View the full topic](https://discuss.elastic.co/t/error-after-migration-elastic-fleet-server-error-failed-version-compatibility-check-with-elasticsearch-x509-certificate-signed-by-unknown-authority/380288)._