ASP.NET and Graph work only in certain condition

Let’s start by saying that this problem make me crazy 🙂

Backgroung info:
I need to add Graph support to an old project ASP.NET, Framework 4.7.2 and webform.
I know, it’s an old and crap technology, but I need it works.

The code (C#) below works fine in a new project ASP.NET core Web App template

    
using Azure.Identity;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Graph;
using Microsoft.Graph.Models;


namespace WebApplication_testGraph.Pages
{
    public class IndexModel : PageModel
    {
        private readonly ILogger<IndexModel> _logger;
   
        public IndexModel(ILogger<IndexModel> logger)
        {
            _logger = logger;
        }

        public void OnGet()
        {

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

            var tenantId = "xxx";

            // Values from app registration
            var clientId = "xxx";
            var clientSecret = "xxx";

            // using Azure.Identity;
            var options = new TokenCredentialOptions
            {
                AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
            };

            // https://learn.microsoft.com/dotnet/api/azure.identity.clientsecretcredential
            var clientSecretCredential = new ClientSecretCredential(
                tenantId, clientId, clientSecret, options);

            var accessToken =  clientSecretCredential.GetTokenAsync(new Azure.Core.TokenRequestContext(scopes) { });

           // Console.WriteLine(accessToken.Token);

            var graphClient = new GraphServiceClient(clientSecretCredential, scopes);

            var requestBody = new Microsoft.Graph.Users.Item.SendMail.SendMailPostRequestBody
            {
                Message = new Message
                {
                    Subject = "Meet for lunch?",
                    Body = new ItemBody
                    {
                        ContentType = BodyType.Text,
                        Content = "The new cafeteria is open.",
                    },
                    ToRecipients = new List<Recipient>
        {
            new Recipient
            {
                EmailAddress = new EmailAddress
                {
                    Address = "[email protected]",
                },
            },
        },
                },
                SaveToSentItems = false,
            };

             graphClient.Users["[email protected]"].SendMail.PostAsync(requestBody);
        }

    }
}

But in a project with ASP.NET Framework 4.7.2, C# and Web Form, about the same code do not work.
I have no errors, but nothing really happens

this is the code:

using Azure.Identity;
using Microsoft.Graph;
using Microsoft.Graph.Me.SendMail;
using Microsoft.Graph.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;


public partial class test_email : System.Web.UI.Page
{
    protected async Task Page_LoadAsync(object sender, EventArgs e)
    {
       
        var scopes = new[] { "https://graph.microsoft.com/.default" };

        var tenantId = "xxx";

        // Values from app registration
        var clientId = "xxxx";
        var clientSecret = "xxxx";

        // using Azure.Identity;
        var options = new TokenCredentialOptions
        {
            AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
        };

        // https://learn.microsoft.com/dotnet/api/azure.identity.clientsecretcredential
        var clientSecretCredential = new ClientSecretCredential(
            tenantId, clientId, clientSecret, options);

        var accessToken = await clientSecretCredential.GetTokenAsync(new Azure.Core.TokenRequestContext(scopes) { });

        //Console.WriteLine(accessToken.Token);

        var graphClient = new GraphServiceClient(clientSecretCredential, scopes);

        var requestBody = new Microsoft.Graph.Users.Item.SendMail.SendMailPostRequestBody
        {
            Message = new Message
            {
                Subject = "Meet for lunch?",
                Body = new ItemBody
                {
                    ContentType = BodyType.Text,
                    Content = "The new cafeteria is open.",
                },
                ToRecipients = new List<Recipient>
        {
            new Recipient
            {
                EmailAddress = new EmailAddress
                {
                    Address = "[email protected]",
                },
            },
        },
            },
            SaveToSentItems = false,
        };

        await graphClient.Users["[email protected]"].SendMail.PostAsync(requestBody);

            }
}

Could you help me to understand why the code do not work in this conditions, please?

TNX

I tryed to change

protected async Task Page_LoadAsync(object sender, EventArgs e)

in

public async Task Page_LoadAsync(object sender, EventArgs e)