Help troubleshooting HDMI port on l502x

My hdmi port has worked fine in the past and i think it still does. I'll plug my xps into my toshiba TV and set the display to extend across the monitors and then nothing appears on the tv. But when I open up both the intel video settings and the Nvidia display settings, both detect that there is another external monitor connected. Now i know the cable is in working order because it connects my xbox to the tv. Any help is much appreciated.

Thanks in advance