Please try the following troubleshooting steps:

 1. Confirm that the USB-C port on your laptop supports DP Alt Mode (video output). Refer to your laptop's user manual, contact the manufacturer, or visit the official website. If the port doesn't support DP Alt Mode, the hub cannot output video to an external monitor.

2. Update your laptop's graphics driver to the latest version to help resolve display-related issues.

3. Try using the hub with a different laptop that has a USB-C port known to support DP Alt Mode.

4. Use a different HDMI or VGA cable, or connect to another monitor to check for hardware issues.

5. Unplug the hub from your laptop and disconnect all connected devices. Wait at least 5 minutes, then restart your laptop and reconnect the hub to see if the issue is resolved.