Is it possible for c# (winform) to get iCloud contact list? Does apple have an API for that on C#?

I found somes examples for getting iCloud contact list on python and NodeJS, I wonder there is one on C#(winform).

The examples I found are:

Python: https://github.com/mindcollapse/iCloud-API/blob/master/iCloud.py

NodeJS: https://www.snip2code.com/Snippet/65033/Request-Contact-List-From-iCloud

When parsing these code to C#, I successfuly call authenticated url to get my contact server address, dsid...

But when I try to call get contact list url, server returns me 421:Client Error, I dont know why that happens ! Does Apple support C# or not ?

My get contact list url:

https://p35-contactsws.icloud.com/co/startup?clientBuildNumber=1P24&clientId=MyGuid&clientVersion=2.1&dsid=MyDSID&locale=en_US&order=last%2Cfirst

Note: https://p35-contactsws.icloud.com is my contact server, it actually is https://p35-contactsws.icloud.com:443, but base on example I refer to, the port :443 need to be removed.

Please someone help me.