Diagnosis
The communication link between the computer and monitor is broken. This requires a specific USB data connection, not just the video cable.
How to Fix It
For USB-C video connection: ensure the single USB-C cable is connected securely at both ends. For HDMI/DisplayPort connection: you must connect the included USB-B to USB-A cable from the monitor's USB-B upstream port to your computer. Install the latest version of BenQ Display Pilot from the BenQ support site for the PD2706U. Restart both computer and monitor.
If That Didn't Work
The monitor may need a driver. On Windows, check Device Manager > Monitors. Right-click on the BenQ monitor, select Update Driver, and browse to the driver file included in the Display Pilot download. On Mac, the connection is typically plug-and-play over USB-C.
Heads Up
Display Pilot requires the monitor to be in the PC mode for full control. Some preset color modes (like Animation or CAD/CAM) may limit software access. Switch to a standard mode like sRGB in the OSD first.