Diagnosis
The monitor's built-in power saver is activating because it is not detecting active signal changes from the video source during static content like videos.
How to Fix It
1. Press the multifunction button to open the OSD.
2. Navigate to 'Menu' > 'System Setup'.
3. Select 'Power Saver'.
4. Change the setting from 'On' to 'Off'. This disables the monitor's internal sleep timer.
5. The monitor will now only enter sleep when your computer tells it to via the video signal (DPMS).
If That Didn't Work
Control the sleep behavior from your computer's operating system. On Windows, go to Settings > System > Power & Sleep. Set 'Screen' to 'Never' while plugged in. This lets your PC manage the sleep signal sent to the monitor.
Heads Up
With 'Power Saver' off, the monitor's backlight will remain on whenever it receives any signal, even a static one. This can lead to slight backlight wear and higher energy use. Ensure your PC is configured to sleep or turn off the display appropriately.