OK, from Security for Elasticsearch is now free article published on May 20th, 2019; I understand that only three core security features are free now, but AD/LDAP is not.
Is this the reason why I am getting those messages?
Is it possible to test it as a part of demo license?
Security is free, starting in versions 6.8.0 and 7.1.0
For a change this important, we wanted to make sure that it was available to as many people as possible, so today we are releasing versions 6.8.0 and 7.1.0 of the Elastic Stack. These versions do not contain new features; they simply make the following core security features free in the default distribution of the Elastic Stack:
- TLS for encrypted communications
- File and native realm for creating and managing users
- Role-based access control for controlling user access to cluster APIs and indexes; also allows multi-tenancy for Kibana with security for Kibana Spaces
Previously, these core security features required a paid Gold subscription. Now they are free as a part of the Basic tier. Note that our advanced security features — from single sign-on and Active Directory/LDAP authentication to field- and document-level security — remain paid features. See the full feature matrix for details.
Also there are another discussions about same/similar errors solved by curl -u <user_here> 'http://localhost:9200/_xpack/security/_authenticate?pretty' command.
From <https://discuss.elastic.co/t/x-pack-kibana-failed-to-authenticate-user/117193/4>