Diagnosis
The monitor is powered on but not receiving a valid video signal from your PC. The most likely cause is a loose or faulty DisplayPort/HDMI cable connection.
How to Fix It
First, verify the physical connections. Power off both the monitor and PC. Reseat the DisplayPort or HDMI cable at both ends—monitor and graphics card. Ensure the cable is fully clicked into the monitor's port. Power the devices back on in sequence: monitor first, then PC.
If That Didn't Work
Test the monitor's internal self-test. Disconnect the video cable completely. The "No Signal" message should appear. Press the monitor's rear joystick to open the OSD. If the OSD appears, the monitor is functional and the issue is source-side. Try a different video cable and a different video output port on your graphics card.
Heads Up
If using DisplayPort, ensure your graphics driver is updated. Some systems require a BIOS/UEFI setting to enable DisplayPort output. The monitor will not wake from sleep if connected via HDMI and the source PC is using a discrete NVIDIA GPU with older drivers—update to the latest driver.