I think you might be hitting one of the restrictions of TeamViewer in a server.
When you install TeamViewer on a server, the software will assign the whole server an ID, then each user their own ID.
However, Users are only activated in the OS when you connect via RDP, so before then the device will show as offline or display a black screen when connected.
Can you open the "ABout TeamViewer section on this device? It will show a server ID and user ID. try connecting with the server ID.
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