MessagesController doesn't exist in my controller code example
Example 1: 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');
Example 2: laravel target class does not exist
Uncomment this line in app>>provider>>RouteServiceProvider.php file
// protected $namespace = 'App\\Http\\Controllers';