Problem with Spark & Stripe, can't make API call

I just installed Spark & Stripe.

When I try to purchase subscription I will get an error:

You don't have permission to access this resource at /vendor/laravel/cashier-paddle/src/Cashier.php:158)

Which means it fails at making API call (assuming to Stripe portal?). I tried to log this API call and Api call returns following:

{"success":false,"error":{"code":107,"message":"You don't have permission to access this resource"}}

So it fails at authentication?

In .env file I have following:

CASHIER_CURRENCY=USD
CASHIER_CURRENCY_LOCALE=en
STRIPE_KEY=pk_test_51LzCI..................
STRIPE_SECRET=sk_test_51LzC5u.......................
STRIPE_WEBHOOK_SECRET=we_1LzC.................

Do you have any idea why this call could be failing? Or what the problem is?