Emailed gifts not received by winners

From your post, I assume that you mean you have gift copies in your inventory from back when we could buy and store games to gift later?

I had the same issue with some of my early giveaways, when I tried to give away some leftover gifts in my inventory. I recall at least one user receiving it via email, but most of them said they didn't get it. I imagine that Steam might have issues delivering the gift emails (and likely has no motivation to fix it), given that the whole inventory gift thing is no longer supported. Easiest solution would be to send them a friend request (and maybe notify them of it on here so they know it's you), then gift them the game via Steam directly.

As long as you didn't get a notification yet that your emailed gift was received, there's no need to worry that the wrong person got it, either.

Yeah I always avoided using the provided emails, half of them look made up anyways