Paths and other habitat barriers will affect this. If you try placing it just in the middle of your zoo with nothing around, I'm sure it'll work. So try deleting the paths and barriers close to where you want to put it. If there's some water somewhere close that'll have to be deleted as well. Try moving it around a little bit and keep trying, it'll work eventually. It takes some work and you'll have to put the paths down again and barriers. Hope this helps a bit.

Usually when this happens it's due to terrain modifications within the blueprint. I will place the blueprint in an open area to see what is in the habitat to try to place it better where I want it. Then CTRL-Z to remove everything before placing it where I want it. If you know where it's going to modify the ground and place water, etc. it's easier to see where it needs more space.

If you still have problems placing it, often it only takes a small movement in one way or another to get it to place. Watch the color of the Blueprint, it will usually show red if it won't place and the red will go away when it's ok. (usually) It can be squirrely at times though.