Terrain Collider: Mesh collider is not supported on terrain at moment

Unity Engine
1

I recently started experimenting with terrain and when I place rocks with a mesh collider using the terrain option to place trees and entering play mode this error comes up:
** Mesh collider is not supported on terrain at moment **

I tried searching online but basically the only thing I found was this 5 year old thread where I should untick the “Convex” option in the mesh collider. Did it and no success.

Can anyone help with this issue?

2

Still have the same problem but i attached a box collider and said the same thing