Sharing an iCloud calendar to other people causes a redirect loop (CalDav - HTTP 301)

A friend of mine shared an iCloud calendar obtaining a WebDav URL, similar to this one:

webcal://p55-caldav.icloud.com/published/2/verylong-token-token-token

For a couple of years, since 2020, it worked perfectly. **Problem**: now, this iCloud URL causes an error "**too many redirects**" in whatever calendar app (e.g. nextCloud, WebDav Sync Adapter, Evolution, Thunderbird, etc.). To further understand the situation I tried with cURL (omissis token):

$ curl --verbose --location http://p55-caldav.icloud.com/published/2/verylong-token-token-token 

HTTP/1.1 301 Moved Permanently
Server: AppleHttpServer/57b15408e9be
Date: Wed, 16 Mar 2022 09:23:06 GMT
Location: https://p55-caldav.icloud.com/published/2/verylong-token-token-token 

...

HTTP/1.1 301 Moved Permanently
Server: AppleHttpServer/57b15408e9be
Date: Wed, 16 Mar 2022 09:23:06 GMT
Location: https://p55-caldav.icloud.com/published/2/verylong-token-token-token 

...

HTTP/1.1 301 Moved Permanently
Server: AppleHttpServer/57b15408e9be
Date: Wed, 16 Mar 2022 09:23:06 GMT
Location: https://p55-caldav.icloud.com/published/2/verylong-token-token-token 

...

HTTP/1.1 301 Moved Permanently
Server: AppleHttpServer/57b15408e9be
Date: Wed, 16 Mar 2022 09:23:07 GMT
Location: https://p55-caldav.icloud.com/published/2/verylong-token-token-token 

...

Now we are inside a very long **redirect loop** and then it quits with the related error:

* Maximum (50) redirects followed
curl: (47) Maximum (50) redirects followed

What's the problem? How to fix this? Has this happened to you? If it helps, this calendar is probably gigantic. But if it was giant it should give a timeout or an error 500 or whatever but not a redirect on that same page, causing even more iCloud overload. Is this a bug? Thank you for your ideas! --- Edited from comments: I tried using https instead of http. Nothing better happened.