On installing an OES service, the core agent and dashboard agent service will be installed on the OES system. These agent services will try to contact the CIS server and if not available the agent services will stop. Ensure that these services are always running else the communication failure results in an empty page.
To view the health of the services, do the following:
On the OES server, restart the Core agent service.
systemctl restart oes-core-agent.service
On the OES server, restart the Dashboard agent service.
systemctl restart oes-dashboard-agent.service
When the core and dashboard agents are running successfully, then the OES Health page displays the health of the OES servers.