I have an HP Spectre x360 laptop and just purchased my 3rd HP 27er Monitor. My old docking station did not accommodate 3 monitors so I purchased your docking station ud-ultcdl. It will not work with 3 monitors. I unplugged all the monitors and only plug 1 monitor in the HDMI 4k port and it will not recognize it. What am I doing wrong? The 2 other ports work fine.