Mixed Reality Capture Feedback for Epic

Hi,
I have purchased Magewell USB Capture HDMI 4K Plus and connected my DSLR camera through the capture card on my desktop computer and it doesn’t work. It shows only a white blank screen. I tested on another similar configuration and it won’t work. After I connected to my DELL M6700 Laptop and it captures the video from DSLR. Need help to solve this issue.