OCI Logging service: fluentd.conf for on-prem host

[etc-fstab]

Hi, this is an issue about on-prem host (OL8) not able to log to OCI logging service.
This is for Oracle internal tenancy. I am able for call and troubleshoot, if needed.

The service unified-monitoring-agent is running and produces errors: "Standard Error received sending request: uninitialized constant OCI::Auth::Signers::ResourcePrincipalsFederationSigner".

I'd like to verify content of the file /etc/unified-monitoring-agent/conf.d/fluentd_config/fluentd.conf, likely the issue is in it.
The file reads:

<source>
@type tail
tag sometag
path /var/log/*
exclude_path /var/log/wtmp
pos_file /etc/unified-monitoring-agent/pos/sometag
 <parse>
 @type syslog
 </parse>
</source>

<match hostname.**>
@type oci_logging
log_object_id ocid1.log.oc1.iad.am-----sq
 <principal>
    @type  user
    oci_config_profile "DEFAULT"
 </principal>
 <buffer tag>
  @type file
  path /opt/unified-monitoring-agent/run/buffer/hostname
 </buffer>
</match>

[etc-fstab]

Resolved with unified-monitoring-agent version 2.5.8-0