How to block crawling of the origin when Azure CDN is configured

Question

something is not clear using Azure CDN. I explain step by step what I have done since my website has been created. Call my website www.mypublicwebsite.com. So:

1. I created a web app on Azure. The website has the following url: https://mypublicwebsite.azurewebsites.net;
2. I created a custom domain www.mypublicwebsite.com
3. I redirected all the request from https://mypublicwebsite.azurewebsites.net to www.mypublicwebsite.com. So I solved the problem of duplicated contents for crawlers.

Everything is fine. Then, I decided to create CDN, according the documentation. Here the confusion starts.

4. I created the CDN profile
5. I created the endpoint. The endpoint has a new url https://mypublicwebsite.azureedge.net
6. I deleted the custom domain from web app;
7. I created the custom domain in cdn profile.

So the current state is this:

This situation is really problematic for SEO!! It cannot be the correct configuration. My contents are triplicated. I partially solved the situation:

8. I redirected all the request from https://mypublicwebsite.azureedge.net to www.mypublicwebsite.com. So I solved the problem of duplicated content for crawlers.

But crawler (and perhaps users?) can still navigate the origin web site. I have been looking for different solutions:

• Make a redirect from https://mypublicwebsite.azurewebsites.net to www.mypublicwebsite.com. But this create a infinite redirects loop between the CDN and the origin.
• Try to hide the origin, but how?

I am honestly starting thinking this is not the correct way to manage cdn. Can anyone help me please?

Thank you