I use a Dell XPS 9570 (i5 Model)
UPDATE: The 4k Connection is being detected by Windows but there is no signal going into the monitor.
I used to use the 2k connection and the 4k connection but for some reason now when I turn on my laptop and connect the Plugable USB-C 4K Triple Display Docking Station, the 4k connection will not work as my monitor is picking up no signal from it. The 2K connection works fine. Now I have to use the VGA Connection and I do not like it as the resolution is worse than the 4K connection. I do not know why the 4k connection does not work since it used to work for me. I have swapped over the connections and it is not the monitors that is the problem, it is the 4k slot. But the 4k Slot used to work for me.
My 2 monitors: https://www.amazon.co.uk/Samsung-C24F390-24-Inch-Curved-Monitor/dp/B01BCF06LE/ref=sr_1_1?ie=UTF8&qid=1547382893&sr=8-1&keywords=Samsung+24+curved