How do request a correct access token in ASP.NET Core for Azure AD to access Microsoft Graph

    private async Task OnAuthorizationCodeReceived(AuthorizationCodeReceivedContext context)
    {
        // Acquire a Token for the Graph API and cache it using ADAL.  In the TodoListController, we'll use the cache to acquire a token to the Todo List API
        string userObjectId = (context.Ticket.Principal.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier"))?.Value;
        ClientCredential clientCred = new ClientCredential(ClientId, ClientSecret);
        AuthenticationContext authContext = new AuthenticationContext(Authority, new NaiveSessionCache(userObjectId, context.HttpContext.Session));
        AuthenticationResult authResult = await authContext.AcquireTokenByAuthorizationCodeAsync(
            context.ProtocolMessage.Code, new Uri(context.Properties.Items[OpenIdConnectDefaults.RedirectUriForCodePropertiesKey]), clientCred, GraphResourceId);

        // Notify the OIDC middleware that we already took care of code redemption.
        context.HandleCodeRedemption();
    }

            string userObjectID = (User.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier"))?.Value;
            AuthenticationContext authContext = new AuthenticationContext(Startup.Authority, new NaiveSessionCache(userObjectID, HttpContext.Session));
            ClientCredential credential = new ClientCredential(Startup.ClientId, Startup.ClientSecret);
            result = await authContext.AcquireTokenSilentAsync(Startup.TodoListResourceId, credential, new UserIdentifier(userObjectID, UserIdentifierType.UniqueId));

.AddOpenIdConnect(opts =>
{
    Configuration.GetSection("Authentication").Bind(opts);

    opts.Events = new OpenIdConnectEvents
    {
        OnAuthorizationCodeReceived = async ctx =>
        {
            var request = ctx.HttpContext.Request;
            var currentUri = UriHelper.BuildAbsolute(request.Scheme, request.Host, request.PathBase, request.Path);
            var credential = new ClientCredential(ctx.Options.ClientId, ctx.Options.ClientSecret);

            var distributedCache = ctx.HttpContext.RequestServices.GetRequiredService<IDistributedCache>();
            string userId = ctx.Principal.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;

            var cache = new AdalDistributedTokenCache(distributedCache, userId);

            var authContext = new AuthenticationContext(ctx.Options.Authority, cache);

            var result = await authContext.AcquireTokenByAuthorizationCodeAsync(
                ctx.ProtocolMessage.Code, new Uri(currentUri), credential, ctx.Options.Resource);

            ctx.HandleCodeRedemption(result.AccessToken, result.IdToken);
        }
    };
});

public class AdalDistributedTokenCache : TokenCache
{
    private readonly IDistributedCache _cache;
    private readonly string _userId;

    public AdalDistributedTokenCache(IDistributedCache cache, string userId)
    {
        _cache = cache;
        _userId = userId;
        BeforeAccess = BeforeAccessNotification;
        AfterAccess = AfterAccessNotification;
    }

    private string GetCacheKey()
    {
        return $"{_userId}_TokenCache";
    }

    private void BeforeAccessNotification(TokenCacheNotificationArgs args)
    {
        Deserialize(_cache.Get(GetCacheKey()));
    }

    private void AfterAccessNotification(TokenCacheNotificationArgs args)
    {
        if (HasStateChanged)
        {
            _cache.Set(GetCacheKey(), Serialize(), new DistributedCacheEntryOptions
            {
                AbsoluteExpirationRelativeToNow = TimeSpan.FromDays(1)
            });
            HasStateChanged = false;
        }
    }
}

[Authorize]
public class HomeController : Controller
{
    private static readonly HttpClient Client = new HttpClient();
    private readonly IDistributedCache _cache;
    private readonly IConfiguration _config;

    public HomeController(IDistributedCache cache, IConfiguration config)
    {
        _cache = cache;
        _config = config;
    }

    [AllowAnonymous]
    public IActionResult Index()
    {
        return View();
    }

    public async Task<IActionResult> MsGraph()
    {
        HttpResponseMessage res = await QueryGraphAsync("/me");

        ViewBag.GraphResponse = await res.Content.ReadAsStringAsync();

        return View();
    }

    private async Task<HttpResponseMessage> QueryGraphAsync(string relativeUrl)
    {
        var req = new HttpRequestMessage(HttpMethod.Get, "https://graph.microsoft.com/v1.0" + relativeUrl);

        string accessToken = await GetAccessTokenAsync();
        req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

        return await Client.SendAsync(req);
    }

    private async Task<string> GetAccessTokenAsync()
    {
        string authority = _config["Authentication:Authority"];

        string userId = User.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;
        var cache = new AdalDistributedTokenCache(_cache, userId);

        var authContext = new AuthenticationContext(authority, cache);

        string clientId = _config["Authentication:ClientId"];
        string clientSecret = _config["Authentication:ClientSecret"];
        var credential = new ClientCredential(clientId, clientSecret);

        var result = await authContext.AcquireTokenSilentAsync("https://graph.microsoft.com", credential, new UserIdentifier(userId, UserIdentifierType.UniqueId));

        return result.AccessToken;
    }
}