My terrain and map is bugging

i created my map with height and trees placed with default mesh colliders, after that i placed my car and put rigid body on it and a box collider, when i started working on the movement controls on the car and pressed play the , camera which prevously worked perfectly now wanders off the map and my car dissapears, i tryed unduing all the changes i made but even after that the bug persists, and i get an error that mesh colliders on the terrain are not supported at the moment, and even if i delete all the meshes the problem mentions, the error persists mentioning the already deleted meshes.Solutions?

use terrain collider instead of mesh collider on the terrain