Why on http testing I got 401 error with actingAs set?

Question

Adding http testing on laravel 10 site I got 401 error :

 ✘ 1 ItemIsAdded
   ┐
   ├ Expected response status code [201] but received 401.
   ├ Failed asserting that 201 is identical to 401.
   │
   │ /project/vendor/laravel/framework/src/Illuminate/Testing/TestResponse.php:147
   │ /project/tests/Feature/ItemsCrudTest.php:60
   │ /project/vendor/laravel/framework/src/Illuminate/Foundation/Testing/TestCase.php:174

when in test I use actingAs method, but seems it does not work :

public function test_1_ItemIsAdded()
{
    // Test Data Setup
    \Log::info(varDump(self::$loggedUser, ' -1 self::$loggedUser::'));
    $itemModel = Item::factory()->make([
        'user_id' => self::$loggedUser->id
    ]);

    // Test Action
    $response = $this
        ->actingAs(self::$loggedUser, 'api')
        ->postJson(route('items.store'), $itemModel->toArray());
    $response
        ->assertStatus(JsonResponse::HTTP_CREATED); // 201  - ERROR POINTS TO THIS LINE

Calling actingAs I set 2nd parameter 'api', but it does not work.

This request works ok under POSTMAN, 401 error only in http testing and I can not get why? In config/auth.php :

<?php

return [

    'defaults' => [
        'guard' => 'web',
        'passwords' => 'users',
    ],


    'guards' => [
        'web' => [
            'driver'   => 'session',
            'provider' => 'users',
        ],

        'api' => [
            'driver' => 'session',
            'provider' => 'users',
        ],
    ],

    'providers' => [
        'users' => [
            'driver' => 'eloquent',
            'model' => App\Models\User::class,
        ],

    ],

    'passwords' => [
        'users' => [
            'provider' => 'users',
            'table' => 'password_reset_tokens',
            'expire' => 60,
            'throttle' => 60,
        ],
    ],

    'password_timeout' => 10800,

];

In routes/api.php I have :

use App\Http\Controllers\Api\ItemController;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;

Route::middleware('auth:sanctum')->get('/user', function (Request $request) {
    return $request->user();
});

Route::middleware('auth:sanctum') ->group(function () {
    Route::apiResource('items', ItemController::class);
    ...

I have .env.testing file, but have I to add some specific options to it ?

How to make tests working ?

"laravel/framework": "^10.10",
"laravel/sanctum": "^3.3",

Thanks in advance!