Why is the R4 card not working?

So I downloaded some games onto my memory card and was going to use the R4 cards I have at home. However, my ds didn’t read the card like the game card slot was empty. So i got a new R4 card and now its able to detect it but when i click on it, it doesn’t show me the games i downloaded, instead there’s an image of a memory card with a ? in it.