Unity Tree Brush tool is not placing my tree models

https://docs.unity3d.com/Documentation/Components/terrain-Trees.html

Creating Trees

Trees can be created in two ways to the terrain engine:

The first one is by using the Tree creator that Unity comes with, and the second one is by using a 3rd party modeling program compatible with Unity, in this case every tree should consist of a single mesh with two Materials. One for the trunk and one for the leaves.

For performance reasons, triangle count should be kept below 2000 for an average tree. The fewer triangles the better. The pivot point of the tree mesh must be exactly at the root of the tree, that is at the point where the tree should meet the surface it is placed on. This makes it the easiest to import into Unity and other modelling applications.

Trees must use the Nature/Soft Occlusion Leaves and Nature/Soft Occlusion Bark shader. In order to use those shaders you also have to place the tree in a special folder that contains the name "Ambient-Occlusion". When you place a model in that folder and reimport it, Unity will calculate soft ambient occlusion specialized for trees. The "Nature/Soft Occlusion" shaders need this information. If you don't follow the naming conventions the tree will look weird with completely black parts.