Je vous ai écrit une démonstration, essayez l'application console simple ci-dessous :
using Microsoft.Graph;
using Microsoft.Graph.Auth;
using Microsoft.Identity.Client;
using System;
using System.Collections.Generic;
namespace sendEmails
{
class Program
{
static void Main(string[] args)
{
var appID = "";
var appSec = "";
var tenantID = "";
IConfidentialClientApplication confidentialClientApplication = ConfidentialClientApplicationBuilder
.Create(appID)
.WithTenantId(tenantID)
.With