Exchange web服务连接失败

我想用不同的方法将电子邮件发送到其他人的邮箱

然后,我找到了Exchange Web服务,因此我尝试执行基本示例:

class Program
{
    static void Main(string[] args)
    {
        //note that there no option for exchange server 2016 (my exchange online use exchange server 2016), so i use the default option  
        ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);   

        service.Credentials = new WebCredentials("user@domain.com", "myPassword");
        service.UseDefaultCredentials = false;

        //for log purpose
        service.TraceEnabled = true; 
        service.TraceFlags = TraceFlags.All;

        service.AutodiscoverUrl("user@domain.com", RedirectionUrlValidationCallback);

        EmailMessage email = new EmailMessage(service);
        email.ToRecipients.Add("user2@domain.com");
        email.Subject = "HelloWorld";
        email.Body = new MessageBody("This is the first email I've sent by using the EWS Managed API.");
        email.Send();

    }

    private static bool RedirectionUrlValidationCallback(string redirectionUrl)
    {
        // The default for the validation callback is to reject the URL.
        bool result = false;

        Uri redirectionUri = new Uri(redirectionUrl);

        // Validate the contents of the redirection URL. In this simple validation
        // callback, the redirection URL is considered valid if it is using HTTPS
        // to encrypt the authentication credentials. 
        if (redirectionUri.Scheme == "https")
        {
            result = true;
        }
        return result;
    }
}  

AutoDiscoveryURL中有一个例外,如下所示:

Microsoft.Exchange.WebServices.Data.ServiceXmlDeserializationException: 'The 
expected XML node type was XmlDeclaration, but the actual type is Element.'  

我已经将名称服务器更改为

ns2.bdm.microsoftonline.com

但仍然不能解决我的问题。。

谢谢。。