How to download Attachments

Hi,

I would like to download the attachment for a particular doc type using c#.
Can anyone help me on this?

The code that am using is given below.

            var httpClient = new HttpClient();
            var response = await httpClient.GetAsync("https://mplify.frappe.cloud//private/files/xxx.pdf");

But am getting 403, forbidden response.

Regards,
Prasanth