This is just a hunch. Sure the adapter supports every subsampling, but perhaps the TV/card do not. Maybe the card is defaulting to 4:4:4 or 4:2:2 and has no ability to output 4:2:0. At the same time, the TV might only be able to use 4:2:0, and will show “No Signal” when it sees 4:4:4 or 4:2:2 coming from the graphics card.