无法使用EWS在Office 365组日历中创建约会

Question

我正在尝试使用带有以下C＃代码的Exchange Web服务API在Office 365组（统一组）日历中创建约会（而不是会议）。

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2013_SP1);
service.UseDefaultCredentials = false;
service.Credentials = new NetworkCredential("admin@officedomain.com", "pwd");
service.Url = new Uri("https://outlook.office365.com/Ews/Exchange.asmx");
service.PreAuthenticate = false;

Appointment appointment = new Appointment(service);
// Set the properties on the appointment object to create the appointment.
appointment.Subject = "Tennis lesson";
appointment.Body = "Focus on backhand this week.";
appointment.Start = DateTime.Now.AddDays(2);
appointment.End = appointment.Start.AddHours(1);
appointment.Location = "Tennis club";
appointment.ReminderDueBy = DateTime.Now;
Folder rtFolder1 = Folder.Bind(service, new FolderId(WellKnownFolderName.Calendar, "o365group@officedomain.com"));
appointment.Save(rtFolder1.Id, SendInvitationsMode.SendToNone);

日历事件已成功创建。但我的问题是，它被创建为会议而不是约会。 正如您在上面的代码中看到的那样，我没有添加任何与会者，但是当我在OWA中打开组日历事件时，它会将凭据用户（admin@officedomain.com）显示为与会者，这迫使我不要取消选中“发送邀请”选项到该组“如下图所示。

任何人都可以帮我解决这个问题吗？