Target class [config] does not exist. code example

Example 1: Target class [] does not exist.

composer dump-autoload

Example 2: Target class does not exist.

use App\Http\Controllers\UserController;

Route::get('/users', [UserController::class, 'index']);
// or
Route::get('/users', 'App\Http\Controllers\UserController@index');

Example 3: Target class does not exist.

Route::get('/', 'App\Http\Controllers\RegistrationController@create');

Example 4: Target class [ExamSeeder] does not exist.

php composer dump-autoload
php artisan migrate:refresh --seed