C# 无法通过API在Google日历中插入新事件

我使用Google Calendar v3、OAuth2，我可以登录、查询事件提要，但我无法通过api插入新事件。日历是公开和共享的。以下是我的示例代码：

AtomEntry entry = new AtomEntry();
AtomPerson author = new AtomPerson(AtomPersonType.Author);
author.Name = "xx";    author.Email = "xx@yahoo.com";
entry.Authors.Add(author);    entry.Title.Text = "Test";
entry.Content.Content = "Test";
calname = "678546u3ua4e1cgc2g1ugku1kg@group.calendar.google.com";
feedUrl = "https://www.googleapis.com/calendar/v3/calendars/{0}/events";
Uri postUri = new Uri(string.Format(feedUrl,calname));
AtomEntry insertedEntry = CalService.Insert(postUri, entry);

我得到这个错误：

[WebException: The remote server returned an error: (401) Unauthorized.]
   System.Net.HttpWebRequest.GetResponse() +6542104
   Google.GData.Client.GDataRequest.Execute() +136

[GDataRequestException: Execution of request failed: https://www.googleapis.com/calendar/v3/calendars/678546u3ua4e1cgc2g1ugku1kg@group.calendar.google.com/events]
Can you please provide a working C# sample with all inclusive instructions on how to insert events from a web application after the user has given permission to use their calendar? Thanks!

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检查您为OAuth 2.0访问令牌请求的作用域。要写入日历，您需要与只读不同的权限。请参阅：。您应该确保您请求并获得范围

https://www.googleapis.com/auth/calendar

来自日历所有者。

您正在使用服务帐户吗？如果是，您是否遵循了此链接中提到的域范围委派的步骤