Spotlight requires authentication to connect to the Windows server and retrieve performance data. There are two ways to do this at Windows Server | Connection Details: use Diagnostic Server credentials or fill in the user and password fields. If you choose to fill in the user and password fields, the account must have the privileges required to retrieve server information, query the registry, and access WMI and performance monitor objects. An account with administrative rights to the Windows server allows this.
What can be done in a environments where it is not possible to connect to the Windows server with an account that is a member of the Administrators group?
This information can be found in the deployment guide.