API URL Not found

I am currently trying to access the REST API of Shopware 5. I am using https://my-shop-url/api/articles as the URL, as described in the docs for testing. I have granted API access to my user and have an API key which I use for authentication.

However, if I try to access via Postman, I get a 401 Unauthorized HTML error message. I have tried Basic Auth with the API Key as password. When I try to access https://my-shop-url/api in my browser, I get 404 Not Found. So how do I access the API then?