Token generated outside controller is too long and it's rejected by ConfirmEmail on Controller in MVC C# - asp.net-mvc

Question

I am updating my question as I have made some progress.
Thanks in advance for your support.
Question:
I am using GenerateEmailConfirmationTokenAsync to create a token outside the Controller (it's working fine), but somehow my token is longer than the ones created within the Controller using the GenerateEmailConfirmationTokenAsync and therefore the ConfirmEmail action rejects the token. (Error: Invalid Token).
I have tried Machinekey on webconfig, HttpUtility.UrlEncode, but I am still stuck. How to sort out the Invalid Token error on Controller ConfirmEmail?
Guys, can you help me please!
Thanks.
Here is my Code:
RegisterUser (outside Controller)
public async Task RegisterUserAsync()
{
var store = new UserStore<ApplicationUser>(db);
var UserManager = new ApplicationUserManager(store);
var query = from c in db.Customer
where !(from o in db.Users
select o.customer_pk)
.Contains(c.customer_pk)
select c;
var model = query.ToList();
if (query != null)
{
foreach (var item in model)
{
var user = new ApplicationUser { UserName = item.email, Email = item.email, customerId = item.customerId};
var result = await UserManager.CreateAsync(user);
if (result.Succeeded)
{
string callbackUrl = await SendEmailConfirmationTokenAsync(user.Id);
SmtpClient client = new SmtpClient();
MailMessage message = new MailMessage
{
IsBodyHtml = true
};
message.Subject = "Confirm Email";
message.To.Add(item.email1);
message.Body = "Please confirm your account by clicking here";
client.SendAsync(message, "userToken");
//Assign Role User Here
await UserManager.AddToRoleAsync(user.Id, "Client");
}
}
}
}
SendEmailConfirmation method (outside Controller)
public async Task<string> SendEmailConfirmationTokenAsync(string userID)
{
var store = new UserStore<ApplicationUser>(db);
var UserManager = new ApplicationUserManager(store);
var url = new UrlHelper();
var provider = new DpapiDataProtectionProvider("MyApp");
UserManager.UserTokenProvider = new DataProtectorTokenProvider<ApplicationUser>(
provider.Create("EmailConfirmation"));
string code = await UserManager.GenerateEmailConfirmationTokenAsync(userID);
string encodedCode = HttpUtility.UrlEncode(code);
string callbackUrl = "http://localhost/Accounts/ConfirmEmail?userId=" + userID + "&code=" + encodedCode;
return callbackUrl;
}
where db is
ApplicationdDbContext db = new ApplicationdDbContext();
ConfirmEmail within the Identity Controller (Accounts Controller) - I've created Accounts instead of Account controller but it's working fine.
//
// GET: /Account/ConfirmEmail
[AllowAnonymous]
public async Task<ActionResult> ConfirmEmail(string userId, string code)
{
if (userId == null || code == null)
{
return View("Error");
}
var confirmed = await UserManager.IsEmailConfirmedAsync(userId);
if (confirmed)
{
return RedirectToLocal(userId);
}
var result = await UserManager.ConfirmEmailAsync(userId, code); //Here I get the error (Token Invlaid, despite the token and userId being displayed)
if (result.Succeeded)
{
ViewBag.userId = userId;
ViewBag.code = code;
}
return View(result.Succeeded ? "ConfirmEmail" : "Error");
}
[HttpPost]
[ValidateAntiForgeryToken]
[AllowAnonymous]
public async Task<ActionResult> ConfirmEmail(SetPasswordViewModel model, string userId, string code)
{
if (userId == null || code == null)
{
return View("Error");
}
if (!ModelState.IsValid)
{
return View(model);
}
var result = await UserManager.AddPasswordAsync(userId, model.NewPassword);
if (result.Succeeded)
{
var user = await UserManager.FindByIdAsync(userId);
if (user != null)
{
await SignInManager.SignInAsync(user, isPersistent: false, rememberBrowser: false);
}
return RedirectToLocal(userId);
}
ViewBag.userId = userId;
ViewBag.code = code;
AddErrors(result);
return View(model);
}
I have worked for hours in this code but until now I can't sort it out.
Thanks for any comments or solution. The reason for this approach is that I have to use task scheduler(I'm using fluentscheduler, which is working fine).