No API key provided

I try to connect and create account on stripe side and got error:

> No API key provided. Set your API key when constructing the StripeClient instance, or provide it on a per-request basis using the api_key key in the $opts argument.

My controller

<?php

namespace App\Http\Controllers;

use App\Models\User;
use Illuminate\Database\DatabaseManager;
use Illuminate\Http\Request;
use Stripe\StripeClient;
use Illuminate\Support\Str;
use Stripe\Exception\ApiErrorException;
use Stripe\Stripe;

class SellerController extends Controller
{
    protected StripeClient $stripeClient;
    protected DatabaseManager $databaseManager;

    public function __construct(StripeClient $stripeClient, DatabaseManager $databaseManager)
    {
        $this->stripeClient = $stripeClient;
        $this->databaseManager = $databaseManager;
    }

    public function showProfile($id){
        $seller = User::find($id);

        if(is_null($seller)){
            abort(404);
        }

        return view('seller', [
            'seller' => $seller,
            'balande' => null
        ]);
    }

    public function redirectToStripe($id){
        $seller = User::find($id);

        if(is_null($seller)){
            abort(404);
        } 
        
        if(!$seller->completed_stripe_onboarding){

            $token = Str::random();
            $this->databaseManager->table('stripe_state_tokens')->insert([
                'created_at' => now(),
                'updated_at' => now(),
                'seller_id' => $seller->id,
                'token' => $token
            ]);

            // account id

            if (is_null($seller->stripe_connect_id)) {
    
                // Create account
                $account = $this->stripeClient->accounts->create([
                    'country' => 'FR',
                    'type'    => 'express',
                    'email'   => $seller->email,
                                   
                ]);

                $seller->update(['stripe_connect_id' => $account->id]);
                $seller->fresh();
            }
            $onboardLink =$this->stripeClient->accountLinks->create([
                'account' => $seller->stripe_connect_id,
                'refresh_url' => route('redirect.stripe', ['id' =>$seller->id]),
                'return_utl' => route('save.stripe', ['token' => $token]),
                'type' => 'acccount_onboarding'
            ]);

            return redirect($onboardLink->url);
        }

        $loginLink = $this->stripeClient->accounts->createloginLink($seller->stripe_connect_id);
        return redirect($loginLink->url);
    }

    public function saveStripeAccount($token){
        $stripeToken = $this->databaseManager->table('stripe_state_tokens')
        ->where('token', '=', $token)
        ->first();

        if(is_null($stripeToken)){
            abort(404);
        }

        $seller = User::find($stripeToken->seller_id);

        $seller->update([
            'completed_stripe_unboarding' => true
        ]);

        return redirect()->route('seller.profile', ['id' => $seller->id]);
    }
}

services.php

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Third Party Services
    |--------------------------------------------------------------------------
    |
    | This file is for storing the credentials for third party services such
    | as Mailgun, Postmark, AWS and more. This file provides the de facto
    | location for this type of information, allowing packages to have
    | a conventional file to locate the various service credentials.
    |
    */

    'mailgun' => [
        'domain' => env('MAILGUN_DOMAIN'),
        'secret' => env('MAILGUN_SECRET'),
        'endpoint' => env('MAILGUN_ENDPOINT', 'api.mailgun.net'),
        'scheme' => 'https',
    ],

    'postmark' => [
        'token' => env('POSTMARK_TOKEN'),
    ],

    'ses' => [
        'key' => env('AWS_ACCESS_KEY_ID'),
        'secret' => env('AWS_SECRET_ACCESS_KEY'),
        'region' => env('AWS_DEFAULT_REGION', 'us-east-1'),
    ],
    'stripe' => [
        'key' => env('STRIPE_KEY'),
        'secret' => env('STRIPE_SECRET'),
    ],
];

appserviceprovider

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Schema;
use Carbon;
use Stripe\StripeCLient;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     */
    public function register(): void
    {
        $this->app->singleton(StripeClient::class, function(){
            return new StripeClient(config('stripe.secret'));
           });
    }

    /**
     * Bootstrap any application services.
     */
    public function boot(): void
    {
       $this->app->singleton(StripeClient::class, function(){
        return new StripeClient(config('stripe.secret'));
       });
    }
}

How to fix this error ? i suppose i have to inject to modify somethings about StripeClient no?

In your AppServiceProvider file, you are missing the config file to look for the stripe details. Instead it needs to look like this:

// Option 1:
return new StripeClient(config('services.stripe.secret'));

// Option 2:
return new StripeClient(['api_key' => config('services.stripe.secret')]);

You can test the return value of config by using the dd function (before the return statement), e.g.:

dd(config('services.stripe.secret'));

EDIT:
You only need the singleton definition in the AppServiceProvider register function, not in the boot function.

Finally, you may need to get out of Stripe sandbox mode by using the sk_test_xxxxxxx api key before you can use the sk_live_xxxxxxx api key.

Make sure that the Stripe API key is set in your .env file

STRIPE_KEY=your_stripe_api_key
STRIPE_SECRET=your_stripe_api_secret

Also clear your config cache:

php artisan config:clear

If you're using a caching mechanism, such as OPcache or APC, make sure to clear the cache after updating the configuration files.

php artisan cache:clear