- A* version: [5.25]
- Unity version: [6000]
use Grid Graph，you see this pass is through a cube obstacle at scene left down
You may want to try increasing the Collision testing diameter- it’s currently set to 1 in your Grid Graph settings. Hope that helps 
It also looks like you are using the raycast modifier with physics raycasting enabled. This can make the path go through unwalkable parts of the graph if there are no colliders there.
i means why this 4*4 obstacle can be calculated in path at left down
i want path like this red color
Yes, if you change your collision settings for your graph generation and also heed Aron’s warning above about the Raycast Modifier, it may help.
Give both a look and see if it helps 