It is necessary to use capital Administrator and not lowercase administrator when entering the account details otherwise it will succeed in test connection but fail to gather metrics.
WARN [Collector worker thread 2] com.vmware.vr.vrops.VrAdapter.onCollect - Failed to collect data
com.vmware.vim.binding.vmodl.fault.SecurityError: Access to perform the operation was denied.
A defect in vCenter that accepts any capitalization of Administrator but only correctly entered Administrator will have permission to generate metrics.
A vCenter defect was identified and will be resolved in a future release, workaround is to use capital Administrator to login instead of lower-case administrator
Workaround is to use capital Administrator to login instead of lower-case administrator