1. Check the power cords and connections of the external monitor to see if it is securely connected to the computer
2. Try a different port or slot on the computer if the monitor is not connecting
3. Try a different cable if you are using a VGA or HDMI cable to connect to the monitor
4. Check if the external monitor is turned on and at an optimal resolution setting
5. Restart the computer and the external monitor to see if the connection issue can be resolved
6. Ensure correct display settings are selected in the control panel for the external monitor