can share the Apache config for that, and the dashboard config.

Yes I can - see the attachments
config.yml.txt
opensearch_dashboards.yml.txt
shib.conf.txt
wazuh.conf.txt

can try to edit your opensearch_dashboards to be http insted of https , since i see this error indicate that your request is send by http and trying to reach https , so
1- on opensearch_dashboards edit
opensearch.hosts: http://127.0.0.1:9200

2- on opensearch_dashboards add
server.basePath: "/wazuh"
server.rewriteBasePath: false
and comment below
#uiSettings.overrides.defaultRoute: "/wazuh"
edit this also
opensearch.ssl.verificationMode: none // you will not use SSL now

since you install the wazuh with Docker , your getway will be server IP not localhost

After fix the issue you can start with SSL
opensearch.ssl.verificationMode: certificate
opensearch.hosts: https://127.0.0.1:9200
server.ssl.enabled: true

try and update

Still without success - either without SSL. Message: "Wazuh dashboard server is not ready yet" is now displayed in the internet browser window and in the log is large java message: io.netty.handler.ssl.NotSslRecordException: not an SSL/TLS record: ...

@cerny2022
As i see here
https://forum.opensearch.org/t/opensearch-dashboards-server-is-not-ready-yet/12970/4
can check for username and password on opensearch-dashboards

I am trying to setup proxy authentication as written in: https://opensearch.org/docs/latest/security/authentication-backends/proxy/, but I dont know if this is applicable to wazuh or not (mentioned link is for opensearch ...). I dont use Docker images. I added one additonal user before trying to implement Apache/Shibboleth proxy. So far as I know proxy IDP should only confirm to wazuh that user is authenticated (password is not send to wazuh).

@cerny2022
It seems Dashboard failed to auth with Wazuh indexer , enable the username and password on Dashboard.
and check for SSL

Could you check for the logs?

Hello, I have attached anonymized syslog log.

Regards

M. Cerny
wazuh-log.txt