Try these troubleshooting steps.
Settings > System > Display, and clicking the Detect button.
While in the Display settings, make sure under “Multiple displays” that you’re not using the Disconnect this display option.
Windows key + Ctrl + Shift + B keyboard shortcut to reload the graphics drivers.
Check physical connection:
Unplug the video and power cable from the monitor. Wait one minute. Reconnect the cables.
Try connecting the monitor to another port. If possible, try to connect the monitor to another computer to find out if it’s a problem with monitor or your PC.
Update graphics driver.
It’s possible that you’re seeing a driver issue. If this is case, uninstall the video driver, restart your computer, and reinstall the driver again (Windows 10 should do this automatically).
If possible, download and install the most up-to-date drivers from your manufacturer’s support website.
If you’re still having problems, you may need to rollback to the previous version of Windows 10.