我们可以尝试使用以下代码来实现在点击后确认电子邮件：

public async Task ConfirmEmail(string userId, string code) 
{
   if (userId == null || code == null)
   {
       return View("Error");
   }
   var result = await UserManager.ConfirmEmailAsync(userId, code);
   if (result.Succeeded)
   {
       return View("ConfirmEmail");
   } 
   else
   {
       return View("Error");
   }
}

如果出现点击确认链接后没有设置电子邮件确认的错误，我们需要在SendGrid中进行以下更改：

1. 在SendGrid中创建一个新模板。
2. 编辑模板中的HTML代码以包含电子邮件确认链接。
3. 使用以下代码发送电子邮件：

var apiKey = Environment.GetEnvironmentVariable("NAME_OF_THE_ENVIRONMENT_VARIABLE_FOR_YOUR_SENDGRID_KEY");
var client = new SendGridClient(apiKey);
var from = new EmailAddress("test@example.com", "Example User");
var subject = "Confirm Your Email";
var to = new EmailAddress(email, name);
var plainTextContent = "";
var htmlContent = @"
Hi " + name + ",
" +
"
Please confirm your account by clicking here.
";
var msg = MailHelper.CreateSingleEmail(from, to, subject, plainTextContent, htmlContent);
var response = await client.SendEmailAsync(msg);

上述代码应该能够解决问题，使得在点击链接后可以成功确认电子邮件。