Diagnosis
The monitor is receiving power but not receiving a valid video signal from your source device. The most likely cause is an incompatible video mode or refresh rate setting from your PC or console.
How to Fix It
First, confirm your source device's output settings match the monitor's specifications. Set your device's external display resolution to 1920x1080. Set the refresh rate to 60Hz, not 144Hz, for initial troubleshooting. Use the original USB-C to USB-C cable for both power and video if your device supports it, or ensure the HDMI cable is fully seated.
If That Didn't Work
The issue may be the monitor's own settings. Press the monitor's OSD menu button. Navigate to the 'System' or 'Settings' menu and select 'Reset All'. This will restore factory display settings, which often resolves handshake issues.
Heads Up
Some gaming consoles require you to power cycle them (full restart) after connecting a new display for the correct resolution to be negotiated. Unplug the monitor from power and the console, restart the console, then reconnect.