Why is my computer not recognizing my second monitor?

1. Check if the display switches to the correct input when you switch the input selector on the monitor.
2. Make sure the cable is securely connected from the monitor to the computer.
3. Verify that the monitor is compatible with the computer.
4. If using a laptop, make sure to connect to the dedicated graphics card port.
5. Attempt to connect the monitor to another computer to see if the issue is with the monitor or the computer.