WARN [pool-6369-thread-2] (102) com.vmware.adapter3.vmwareinfrahealth.helpers.vcenter.collector.VCenterHealthServicesCollector.collect - [< FQDN of the vCenter Server >] Unable to get response from the vMON services. Please check if the vCenter MP is configured with admin level credentials
ERROR [pool-28553-thread-4] com.vmware.adapter3.vmwareinfrahealth.util.RestAPISession.getVmonApi - Failed: URL: https://<FQDN-Of-the-vCenter Server>/rest/appliance/vmon/service/vsan-health HTTP error code: 403 Forbidden
Aria Operations 8.18.X
By default, Read Only permission is enough to monitor and gather inventory data, metrics, and properties from vCenter Server. However, if you want to monitor the health of vCenter services using VMware Infrastructure Health, make sure the service account linked to the vCenter Server Adapter is either part of the 'SystemConfiguration.Administrator' group or has administrator-level access to vCenter services
VMware Infrastructure Health is activated by default in the Aria Operations 8.18.X versions and a new VMware Infrastructure Health account is created for each new node and cloud proxy in VMware Aria Operations
Refer:
VMware Infrastructure Health
Permissions Required to Discover vCenter Services