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In the more modern versions of Microsoft Windows (for example Windows 10 & Windows Server 2016) the RDP defaults have changed. The default for “SecurityLayer” has been changed from 0 to 2. Disabling: “Allow connections only from computers running Remote Desktop with Network Level Authentication (recommended)” doesn’t change that value to a 0 either.
This can be fixed in the registry though:
Go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp
Change “SecurityLayer” to 0