Getting wrong callback url for email confirmation in ASP NET Core 6 - asp.net-core

Question

I am having very strange issue with my project. Everything works fine in debugging mode on localhost, but if I will publish it, I am getting the callback url without the https:// prefix. If user will click on the confirm button, some redirection tricky magic is happening as from url http://www.detailandgo.co.uk/Identity/Account/ConfirmEmail?userId=blablabla&code=foobar I am getting https://www.detailandgo.co.ukidentity/Account/ConfirmEmail?userId=blablabla&code=foobar.
As you can see, the url is correct, but I am missing the backslash between base url and "identity". If I will add it manually, everything works nicely. I was reading a lot about it, but haven't found any solution.
I am using ASP NET CORE 6 with Razor pages...
Thank you for all your suggestions and wishing you nice day!!
I've tried googleing a lot, having look in here at Stack Overflow, but haven't found any viable solution.
code which is generating the code:
_logger.LogInformation("User created a new account with password.");
_userManager.Options.SignIn.RequireConfirmedEmail = true;
var userId = await _userManager.GetUserIdAsync(user);
var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
var test = Request.Scheme;
var callbackUrl = Url.Page(
"/Account/ConfirmEmail",
pageHandler: null,
values: new { area = "Identity", userId = userId, code = code, returnUrl = returnUrl },
protocol: Request.Scheme);
string encodedCallBackUrl = HtmlEncoder.Default.Encode(callbackUrl);
Email email = new Email();
using (StreamReader reader = System.IO.File.OpenText(_webHostEnvironment.WebRootPath + "/Email/index.html"))
{
email.From = "info#detailandgo.co.uk";
email.Body = reader.ReadToEnd()
.Replace("{callbackUrl}", encodedCallBackUrl)
.Replace("{firstName}", Input.FirstName)
.Replace("{callbackBook}", Url.Page("/Index"));
email.IsHtml = true;
email.Subject = Input.FirstName + ", confirm your Detail&Go account";
email.To = Input.Email;
}

Answer 1

We can ensure the correctness of the URL through a certain format, as follows:
$"{Request.Scheme}://{Request.Host}/{encodedCallbackUrl.TrimStart('/')}";
I have researched this issue, and I think this should be the workaround or could be the soultion.
Change below below code
var callbackUrl = Url.Page(
"/Account/ConfirmEmail",
pageHandler: null,
values: new { area = "Identity", userId = userId, code = code, returnUrl = returnUrl },
protocol: Request.Scheme);
string encodedCallBackUrl = HtmlEncoder.Default.Encode(callbackUrl);
to
var callbackUrl = Url.Page(
"/Account/ConfirmEmail",
pageHandler: null,
values: new { area = "Identity", userId = userId, code = code, returnUrl = returnUrl },
protocol: Request.Scheme);
string encodedCallBackUrl = HtmlEncoder.Default.Encode(callbackUrl);
encodedCallBackUrl =$"{Request.Scheme}://{Request.Host}/{encodedCallbackUrl.TrimStart('/')}";