When using a call from the ground you need to be careful your not vocalizing directly at the deer from your blind. I try to point the call to my left or right so the deer aren't looking directly in my direction. The other reason is volume. I'm no expert by any stretch but I would guess does bleat from a distance. They wouldn't quietly walk up to a group of other deer and then bleat.

You are probably at or very close to a good spot. One of the nice things about ground blinds is that you can move easily.

When I run into something like you are experiencing, I back off and try to make another approach from downwind. As you approach, look for better shooting lanes and "natural" blind locations like fallen branches, stumps, etc.

Let us know how you do next time out. I never use a tree stand and I don't feel it is a disadvantage at all.