OSMS Plugin shows error "Not Supported" and "plugin disabled in config" for Existing OCI instance

APPLIES TO:

Oracle Cloud Infrastructure - Version N/A and later

Information in this document applies to any platform.

SYMPTOMS

Instance created in 2019, hence by default OS Management tab is not activated.

Activated OS Management plugin in Oracle Cloud Agent tab in OCI Console.

After some time the OS Management Service Agent displays message "Not Supported" and "plugin disabled in config".

Check the version of oracle-cloud-agent in the instance:

$ yum info oracle-cloud-agent
Loaded plugins: langpacks, ulninfo
Repodata is over 2 weeks old. Install yum-cron? Or run: yum 
makecache fast
Installed Packages
Name : oracle-cloud-agent
Arch : x86_64
Version : 1.11.1
Release : 5104.el7
Size : 188 M
Repo : installed
From repo : /oracle-cloud-agent-1.11.1-5104.el7.x86_64
Summary : Oracle Cloud Agent
URL : https://docs.cloud.oracle.com/iaas/
License : https://oss.oracle.com/licenses/upl/
Description : Oracle Cloud Infrastructure agent for management 
and monitoring.