To resolve the issue, re-register the vCenter Server adapter instance in vRealize Operations Manager.
- Log into the vRealize Operations Manager UI as the local admin user.
- Navigate to Administration > Solutions.
- In the Solution tab, select VMware vSphere and click Configure.
- In the Manage Solution window, select the desired vCenter Adapter instance on the left.
- Click Manage Registrations then click Unregister, and OK.
- Click Manage Registrations again.
- Enter Global Administrative credentials for the vCenter, then click Register and OK.
- Click Save Settings.
Re-register vCenter to Usage Meter and check if Usage Meter discover vRealize Operations Manager.