If the Laptop External Monitor is not working ... Similarly, you should check the HDMI cable you use to connect the second display to the Windows 10 laptop. If you are using any kind of converter ...

For example, you can connect two monitors with HDMI and then a third with DisplayPort. Connect the video cable for the first ...

For example, if a cable box or PC has DVI out, but the TV or monitor only has HDMI in, a DVI-to-HDMI adapter cable is used to connect the video. The audio must be cabled separately as DVI ...