Laravel showing {"message":"Unauthenticated."} when accessing api routes

I have an Vue + Laravel application. Here I am using laravel API routes to get the data. For the API auth I am using JWT from this tutorial: https://blog.logrocket.com/implementing-jwt-authentication-laravel-9/

Now I am getting:

{"message":"Unauthenticated."}

error message whne I access to this API route: http://localhost:3000/api/countries

Country.php (Model)

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Factories\HasFactory;

class Country extends Model
{
    use HasFactory;
    
    protected $table = 'countries';

    protected $primaryKey = 'id_country';

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'country_name' ,
        'code'         ,
    ];

}

CountryController.php (Controller)

<?php

namespace App\Http\Controllers;

use App\Models\Country;
use Illuminate\Http\Request;

class CountryController extends Controller
{

    public function __construct()
    {
        $this->middleware('auth:api');
    }
    
    /**
     * @return \Illuminate\Http\JsonResponse
     */
    public function countries()
    {
        $country = Country::get();
        return response()->json($country, 200);
    }

}

api.php

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;
use App\Http\Controllers\Auth\AuthController;
use App\Http\Controllers\CountryController;

Route::controller(CountryController::class)->group(function () {
    Route::get('countries', 'countries')->name("countries");
});

Can you tell me what is wrong here and how can I solve it?