我试图实现OAUTH通过Outlook（Office 365）从各种内部开发的程序发送电子邮件。我已在Azure中创建了一个应用程序注册，并为其授予Mail.ReadWrite、Mail.Send和User.Read权限。我想我漏了一步。
我使用this article作为准则。
我已经添加了Mail.ReadWrite、Mail.Send和User.Read权限。我已经从Office365 ExchangeOnline添加了IMAP.AccessAsApp和SMTP.SendAsApp。此代码块：

private async void SendMailOAUTH(MemoryStream ms, string ServiceName, string DList)
    {
        string authority = $"https://login.microsoftonline.com/{tenantId}";
        string[] scopes = { "https://graph.microsoft.com/.default" };

        IConfidentialClientApplication app = ConfidentialClientApplicationBuilder
            .Create(clientId)
            .WithClientSecret(clientSecret)
            .WithAuthority(authority)
            .Build();

        AuthenticationResult authResult = await app.AcquireTokenForClient(scopes).ExecuteAsync();
        string accessToken = authResult.AccessToken;

        // Create the attachment
        System.Net.Mime.ContentType ct = new("application/vnd.ms-excel");
        System.Net.Mail.Attachment attachment = new(ms, ct);
        attachment.ContentDisposition!.FileName = ServiceName + ".xlsx";

        // Create the email message
        MailMessage serviceMail = new MailMessage(userEmail, DList)
        {
            Subject = ServiceName,
            Body = "Please see the attached spreadsheet."
        };
        serviceMail.Attachments.Add(attachment);

        // Create the SMTP client with OAuth2 authentication
        SmtpClient smtpClient = new SmtpClient("smtp.office365.com", 587)
        {
            EnableSsl = true,
            DeliveryMethod = SmtpDeliveryMethod.Network,
            UseDefaultCredentials = false,
            Credentials = new NetworkCredential(userEmail, accessToken),
            TargetName = "STARTTLS/smtp.office365.com"
        };

        try
        {
            // Send the email
            smtpClient.Send(serviceMail);
        }
        catch (Exception ex)
        {
            _ = ex.Message;
        }
        finally
        {
            // Dispose resources
            smtpClient.Dispose();
            serviceMail.Dispose();
            attachment.Dispose();
        }

    }

调用smtpClient时产生此错误。发送：
“SMTP服务器需要安全连接，或者客户端未经过身份验证。服务器响应为：5.7.57客户端未经验证发送邮件。错误：535 5.7.139身份验证不成功，请求不符合成功身份验证的条件。请与管理员联系。[BY3PR05CA0036.namprd05.prod.outlook.com 2023-06-01T19：15：39.132Z 08DB625E632A34A0]”
我卡住了。有人能帮帮我吗？
我认为问题可能出在作用域上，所以我尝试了string[] scopes = {“https://outlook.office.com/.default“}，但仍然得到相同的错误。
我已经检查了其他文章，并尝试了建议的补救措施，无济于事。