Dell xps 15 9570 Doesn't connect to a specific monitor

Hello,

When I plug in an external monitor via HDMI, the external monitor says "No Device Connected". My laptop flickers and the mouse goes into the center of the screen. Under settings > display, it would say the monitor is connect then unconnected repeatedly. However, when I plug in my laptop to any other external screen it seems like everything is fine and when any other device is connected to the monitor, the monitor displays everything ok. It seems that this combination of my laptop and the monitor is the only one that doesn't work. It used to work about a month ago but I stopped using the monitor until now. 

Any help is appreciated, thanks.