Here are some steps you can take to resolve the issue:

1. Ensure all cables are securely connected

Check all cables connecting your laptop to the external monitor and ensure that everything is connected securely.

2. Verify monitor settings

Navigate to the monitor’s settings and verify that the correct resolution is being used.

3. Update drivers and software

Make sure the drivers and software for your laptop and monitor are up-to-date. Drivers and software for both can usually be found on their manufacturer's website.

4. Adjust laptop display settings

In your laptop display settings, set the external monitor to the correct resolution and enable display scaling.