LDAP Okta Authentication using C# code

Hello,

i created window server in VM from Azure. And also created users and groups over their. Configuration window server LDAP to okta.com is successfully done. So after that okta give me that URL and other details. So when i try to access this URL, username and password from C# code, it’s give me the error like "directory is unavailable or server not operational’.

I dint get the exact error. Can anyone help me ?