When trying to make a Spotlight Windows connection, there are two credentials that need to be in Administrators group on monitored Windows Server.
a. The user running Spotlight - So from the host where Spotlight is installed, this would be the user you logged into your PC as, called UserW in this KB Article.
b. The user that you put into Spotlight Windows connection property, called UserS in this KB Article.
As a result of the above you have three scenarios:
1. If you getting "The Service manager on <server> is not accessible," it means UserW running Spotlight is not in Administrators group on Windows that you want to monitor.
2. If you getting “Access is denied,” it means UserS in the Spotlight Windows connection properties is not in Administrators group on the Windows that you want to monitor.
3. If you getting “Unable to connect to <server>,” it means there is another user from the same Spotlight Windows connection trying to connect to the same monitored Windows. Once you press connect in Spotlight, it keeps connection data in cache until you close the application. The point here is that we need to re-start Spotlight to clear whatever connection info it is holding before trying the next troubleshooting step.