Target class controller [controllerName] not found in Laravel 8

Question

When I hit my register route using Postman, it gave me the following error:

My api.php route:
Route::get('register', 'Api\RegisterController@register');

Here is my controller:

Answer 1

It should be changed to:

Route::get('register', [RegisterController::class, 'register']);

Answer 2

first, in the route add the controller name.

use App\Http\Controllers\RegisterController;

In the route use like this way

Route::get('register', [RegisterController::class, 'register']);