问MailKit、Office 365和OAUTH2:服务器端应用程序身份验证中的问题

EN

    public class Mailer {
    public async static void Send(string subject, string body) {
        string tenantID = "abcdef";
        string clientId = "ghilmn";
        string clientSecret = "opqrst";
        string appName = "MyApp";

        //clientSecret = Uri.EscapeDataString(clientSecret);
        //clientSecret = Uri.EscapeUriString(clientSecret);

        var MyConfidentialClientApplication = ConfidentialClientApplicationBuilder.Create(clientId)
            .WithClientSecret(clientSecret)
            .WithTenantId(tenantID)
            .Build();

        var scopes = new string[] {"https://graph.microsoft.com/.default"};

        try {
            var authToken = await MyConfidentialClientApplication.AcquireTokenForClient(scopes).ExecuteAsync();

            var oauth2 = new SaslMechanismOAuth2(appName, authToken.AccessToken);  //  SaslMechanismOAuth2(appName, authToken.AccessToken);
            var m_client = new SmtpClient(new ProtocolLogger("smtp.log"));
            await m_client.ConnectAsync("outlook.office365.com", 587, SecureSocketOptions.StartTls);
            await m_client.AuthenticateAsync(oauth2);
        }
        catch (Exception ex) {
            Debug.WriteLine(ex.Message);
            // do nothing;
        }
        return;

    }

Eccezione generata: 'MailKit.Security.AuthenticationException' in System.Private.CoreLib.dll
535: 5.7.3 Authentication unsuccessful [ZR0P278CA0036.CHEP278.PROD.OUTLOOK.COM]

        public async Task  Connect_MFA() {
        
        var options = new PublicClientApplicationOptions {
            ClientId = "abcd",
            TenantId = "efgh",
            RedirectUri = "https://login.microsoftonline.com/common/oauth2/nativeclient"
        };

        var publicClientApplication = PublicClientApplicationBuilder
            .CreateWithApplicationOptions(options)
            .Build();

        var scopes = new string[] {
            "email",
            "offline_access",
            //"https://outlook.office.com/IMAP.AccessAsUser.All", // Only needed for IMAP
            //"https://outlook.office.com/POP.AccessAsUser.All",  // Only needed for POP
            "https://outlook.office.com/SMTP.Send", // Only needed for SMTP
        };

        var authToken = await publicClientApplication.AcquireTokenInteractive(scopes).ExecuteAsync();

        var oauth2 = new SaslMechanismOAuth2(authToken.Account.Username, authToken.AccessToken);

        m_client = new SmtpClient(new ProtocolLogger("smtp.log"));
        await m_client.ConnectAsync("outlook.office365.com", 587, SecureSocketOptions.StartTls);
        await m_client.AuthenticateAsync(oauth2);
    }