When you try to project from a Surface Pro, Surface Book, or Surface Laptop to an 84-inch Surface Hub by using the HDMI port on the Surface Hub, the error message "Device Resolution is not supported" is displayed.
The Surface device is not set to a supported 84-inch ingest resolution. By default, Windows tries to connect to the Surface Hub by using Duplicate mode, duplicating your desktop on both screens. But the default resolution of the Surface device is higher than the 1080p resolution of the Surface Hub, and so the Hub is unable to display the higher-resolution image.
Projecting to a second screen can be accomplished by using Extend. Extend is used to expand the desktop user interface across your Surface and Surface Hub displays, allowing each to display the desktop in their native resolution. Either of the two methods described below can be used to configure your Surface to display your desktop in Extend mode.
Method 1: Change the desktop resolution.
Open Start, and then select Settings > System > Display.
Select the Surface Hub display from the choice made available
Under Scale and layout, change the setting under Resolution to 1920 x 1080.
Method 2: Change Project setting to Extend.
Press Windows key+P and then select Extend.