HTTP request failed! HTTP/1.1 403 Forbidden

Why do I often get an answer HTTP request failed! HTTP/1.1 403 Forbidden?

I tested the issue here, but can not recreate it.

=>If you test the connection with Postman, do you get the same result?

You probably know it, but just in case: Postman is a free API testing app.

If you see the problem even with Postman, a screenshot of the result could be helpful.