Hi,
This seems a known issue of Windows Server 2008. Sorry for the inconvenience this has brought.
We can use the IP address to check the accurate result. To do so:
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1. In the Change Directory Server dialog box , we can find "In Change to", select "This Domain Controller or AD LDS instance".
2. In the box below, click the line "<Type a Directory Server name[:port] here>". The line should be selected and ready for editing.
Type the IP address of your Windows Server 2008, press Enter. Is it Online now?
We will forward this issue to product team and post feedback if there is any.
Thanks.