LDAP Authentication Error – ActiveSupport::MessagePack::UnserializableObjectError

Hi everyone,

I’m using the discourse-ldap-auth plugin on a self-hosted Discourse (Docker install).
After a recent rebuild, LDAP authentication started failing for all users.

Here’s the relevant error from production.log:

(ldap) Authentication failure! ldap_error: ActiveSupport::MessagePack::UnserializableObjectError,
Unsupported type Net::BER::BerIdentifiedString for object “******** (Kullanıcı Teknolojileri Yönetim Müdürlüğü)”
Started GET “/auth/failure?message=ldap_error&origin=http%3A%2F%2Fic*ot*rol.va**fb*nk.intra%2Flogin&strategy=ldap”
Processing by Users::OmniauthCallbacksController#failure as HTML
Completed 200 OK

Details

  • The issue affects all LDAP users.

  • All users in our LDAP directory have displayName values containing Turkish characters (ğ, ü, ş, İ, etc.).

  • The error occurs right after the LDAP authentication attempt — no user gets logged in.

Is this a general problem with the latest version of Discourse? Could it be related to a Ruby incompatibility? What solution do you suggest?

1 Like

Hallo Zusammen und Osmanmermer,
wir haben hier seit ein paar Tagen den gleichen Fehler:
(ldap) Authentication failure! ldap_error: ActiveSupport::MessagePack::UnserializableObjectError, Unsupported type Net::BER::BerIdentifiedString for object "username"

  • Das Problem betrifft im Moment die neu angelegten LDAP user die noch nie eingeloggt waren
  • Es ist unabhängig von Sonderzeichen
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I shifted this to 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?

Oops just noticed this is not an official plugin so not officially supported. I also am not immediately finding the plugin topic. We should move this into there. Can someone help find it? I am on the move currently and not at my desk.

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Hallo, Es betrifft das Update auf 3.6.0.beta2 und der Fehler betrifft bei uns nur neuanzulegende Accounts (Ldap user create mode). Bestehende Accounts können sich weiter einloggen. Zurück auf 3.6.0.beta1 ist wieder alles OK . Das LDAP Auth Plugin hat sich nicht verändert.

Sorry to hear you’re having trouble! Unfortunately the LDAP auth plugin is not written by us at Discourse and so is not supported. It does not even have a Plugin topic here. If you need help with it, contact the author on github or start a Marketplace topic to see if an expert in the community is up to the task.