Optiplex 7020, StarTech USB 3.1 card (USB-C - PCIe), no video

I have an Optiplex 7020 with a StarTech 2-port USB 3.1 card (USB-C - PCIe) installed. My monitor is a C3422WE connected with a USB-C cable. I get sound but no video. Device manager says the correct driver is installed but also has a warning sign that the driver is not able to start. (driver is usbvideo.sys) Computer OS is Windows 7. Is there a driver available ?