Hello [NAME] , I think the issue is with the cable you used.  To connect from HDMI (computer) to Displayport (monitor), you will need an active converter cable such of this one. [IMAGE]
My PC has a Nvidia GeForce GTX 1660 Ti video card in it.  This card has 3 ports:  DisplayPort, HDMI, and DVI I tried connecting the DisplayPort to one monitor and the HDMI to the other monitor.  The DisplayPort works.  The HDMI does not.  Windows says it does not detect a second monitor.  I also tried connecting the 2nd monitor to the DisplayPort on the motherboard.  This also does not work.  If I connect the 2nd monitor to the DisplayPort on the GTX 1660 video card it works so it is not the monitor.  Both monitors are the same: Dell E2222H. What am I doing wrong? Fred
XPS 8950, GTX 1660 Ti, connect two monitors E2222H