@Venn Since YouTube's comment system isn't the most helpful, I'll mirror my comment here:

Those cables vary, depending on how much the particular batch-maker decided to pinch pennies. I have some that look identical externally and work fine, but I wound up getting a refund on another that didn't work.

Since then, I've discovered an explanation of what was probably wrong (missing components) and a DIY fix for it at https://karusisemus.wordpress.com/2017/01/02/cheap-usb-midi-cable-how-to-modify-it/