Your purchase page and manual says:
The screen recorder feature assists you in recording anything shown on your screen conveniently. You can record a game walkthrough or a tutorial for sharing on YouTube, blog. As to DRM video, itâ€™s almost impossible to convert iTunes DRM video directly, but this video converter for Mac allows you to record iTunes DRM video without losing too much quality, whereupon you can have the DRM-protected video played on any mobile devices as you like.
But your product doesn’t work in macOS Sierra (version 10.12) on a MacBook Pro trying to record a DRM video on iTunes 188.8.131.52 (the current version).
When I try, the video playing in iTunes goes black.