How can I fix email confirmation - in .NET Core, it doesn't work

Question

I already have a register action

public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
            var useremail = _userManager.Users.FirstOrDefault(u => u.Email.ToLower() == Input.Email.ToLower());

            if (useremail == null)
            {
                returnUrl = returnUrl ?? Url.Content("~/");
                ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();

                if (ModelState.IsValid)
                {
                    var user = new IdentityUser { UserName = Input.UserName, Email = Input.Email };
                    var result = await _userManager.CreateAsync(user, Input.Password);
                    if (result.Succeeded)
                    {
                        _logger.LogInformation("User created a new account with password.");

                        var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
                        code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
                        var callbackUrl = Url.Page(
                            "/Account/ConfirmEmail",
                            pageHandler: null,
                            values: new { area = "Identity", userId = user.Id, code = code },
                            protocol: Request.Scheme);

                        await _emailSender.SendEmailAsync(Input.Email, "Confirm your email",
                            $"Please confirm your account by <a href='{HtmlEncoder.Default.Encode(callbackUrl)}'>clicking here</a>.");

                        if (_userManager.Options.SignIn.RequireConfirmedAccount)
                        {
                            return RedirectToPage("RegisterConfirmation", new { email = Input.Email });
                        }
                        else
                        {
                            await _signInManager.SignInAsync(user, isPersistent: false);
                            return LocalRedirect(returnUrl);
                        }
                    }

                    foreach (var error in result.Errors)
                    {
                        ModelState.AddModelError(string.Empty, error.Description);
                    }
                }
            }
            // If we got this far, something failed, redisplay form
            ViewData["EmailExists"] = "Try another email that one is used";

            return Page();
}

Then I created the sendgrid user and key and registered them by CMD, then I created the action of send email

public class EmailSender : IEmailSender
{
        public EmailSender(IOptions<AuthMessageSenderOptions>optionsAccessor)
        {
            Options = optionsAccessor.Value;
        }

        public AuthMessageSenderOptions Options { get; }

        public Task SendEmailAsync (string email , string subject , string message)
        {
            return Excute(Options.SendGridKey,subject,message,email);
        }

        private Task Excute(string apiKey, string subject, string message, string email)
        {
            var client = new SendGridClient(apiKey);
            var msg = new SendGridMessage()
            {
                From = new EmailAddress("[email protected]", "dary dress"),
                Subject = subject,
                PlainTextContent = message,
                HtmlContent = message
            };

            msg.AddTo(new EmailAddress(email));
            msg.SetClickTracking(false, false);

            return client.SendEmailAsync(msg);
        }
}

Then in startup.cs

public IConfiguration Configuration { get; }

// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<ApplicationDbContext>(options =>
          options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));
    services.AddIdentity<IdentityUser, IdentityRole>( options => options.SignIn.RequireConfirmedAccount = true)
                .AddDefaultUI()
                .AddDefaultTokenProviders()
                .AddEntityFrameworkStores<ApplicationDbContext>();
    services.AddControllersWithViews();
    services.AddRazorPages();
    services.AddMvc();
    services.AddTransient<IEmailSender, EmailSender>();
    services.Configure<AuthMessageSenderOptions>(Configuration);
    services.AddPaging();
    services.ConfigureApplicationCookie(o => {
                o.ExpireTimeSpan = TimeSpan.FromDays(5);
                o.SlidingExpiration = true;
            });
    services.AddMvc(options =>
            {
                options.Filters.Add(new RequireHttpsAttribute());
            });
    services.ConfigureApplicationCookie(options =>
            {
                options.AccessDeniedPath = new Microsoft.AspNetCore.Http.PathString("/Main/AccessDenied");
            });
}

but sending an e-mail doesn't work after registration gives me some words that i need confirm my email and gives me link to confirm my email but doesn't send it to gmail

Does anyone have an idea?

I followed this documentation from microsoft https://learn.microsoft.com/en-us/aspnet/core/security/authentication/accconfirm?view=aspnetcore-3.1&tabs=visual-studio

Answer 1

When I create a new web application with individual user accounts, this works perfectly, but I noticed that when you scaffold identity and override all pages to have control into an existing app, the behavior you are experiencing is the usual.

Here is how I fixed it:

If you open the file Areas/Identity/Pages/Account/RegisterConfirmation.cshtml.cs look for the comment Once you add a real email sender, you should remove this code that lets you confirm the account, comment everything below that line before the return Page() statement and that should do the job.

Answer 2

"Solved" I asked Sendgrid, and I was told that I cannot use my yahoo email (or gmail,...) as the sender email; this is part of the answer: "Yahoo observes an email security standard called DMARC. DMARC instructs email providers to reject messages where the From domain is a Yahoo domain, but the message originates from a non-approved domain server/service." So I need to use my own mail domain;