# LDAP Authentication Error – ActiveSupport::MessagePack::UnserializableObjectError

**URL:** https://meta.discourse.org/t/ldap-authentication-error-activesupport-unserializableobjecterror/385668
**Category:** Bug
**Tags:** auth-plugins
**Created:** [October 15, 2025, 9:18am UTC](https://meta.discourse.org/t/ldap-authentication-error-activesupport-unserializableobjecterror/385668 "2025-10-15T09:18:04Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![tobiaseigen](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/tobiaseigen/32/539204_2.png) [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [October 25, 2025, 6:56pm UTC](https://meta.discourse.org/t/ldap-authentication-error-activesupport-unserializableobjecterror/385668/3 "2025-10-25T18:56:15Z")

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I shifted this to #Contribute > Bug in case it is a bug introduced recently, since it appears to have affected two sites in s similar way.

Has anything changed on your end since last week? Has updating again fixed it?

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_[View the full topic](https://meta.discourse.org/t/ldap-authentication-error-activesupport-unserializableobjecterror/385668)._