Answers for "Target class [BotManController] does not exist."

Target class [Controller] does not exist.

//accessing any function in the controller (this is web.php file)
use App\Http\Controllers\PostsController;

Route::get('/post', 'App\Http\Controllers\PostsController@index');

Target class [UserController] does not exist.

Note: don't forget to import (use) your controller in the routes(web.php) file at the top. Like:
use App\Http\Controllers\PagesController;

Route::get('/',[PagesController::class, 'index']);

Illuminate\Contracts\Container\BindingResolutionException Target class [SlugController] does not exist.

Route::get('/test/{slug}',  'App\Http\Controllers\SlugController@show' );