TOTP Problem - Microsoft Authenticator is not matching the code generated on server

Question

I am getting a not verified using the TOTP method I have found on the following link.

OTP code generation and validation with otp.net

!My! code is below.

1. The _2FAValue line at the top is embedded into the QR barcode that Microsoft Authenticator attaches too.

2. The _Check... Function is the server ajax call to the server which implements OTP.Net library exposing TOTP calculation.

3. MakeTOTPSecret creates an SHA1 version of a Guid which is applied to the User profile and stored in _gTOTPSecret. NB: This IS populated in the places it is used.

4. I think I must have missed something obvious to get a result, here.

   loSetup2FAData._s2FAValue = $@"otpauth://totp/{loUser.UserName}?secret={loUser.MakeTOTPSecret()}&digits=6&issuer={Booking.Library.Classes.Constants._sCompanyName}&period=60&algorithm=SHA1";

        [AllowAnonymous]
    public JsonResult _CheckTOTPCodeOnServer([FromBody] Booking.Site.Models.Shared.CheckTotpData loCheckTotpData)
    {
        string lsMessage = "<ul>";
        try
        {
            string lsEmail = this.Request.HttpContext.Session.GetString("Buku_sEmail");
            Booking.Data.DB.Extensions.IdentityExtend.User loUser = this._oDbContext.Users.Where(U => U.UserName.ToLower() == lsEmail.ToLower() || U.Email == lsEmail).FirstOrDefault();
            if (loUser != null && loUser.Load(this._oDbContext) && loUser._gTOTPSecret != Guid.Empty)
            {
                OtpNet.Totp loTotp = new Totp(Booking.Library.Classes.Utility.StringToBytes(loUser.MakeTOTPSecret()), 60, OtpHashMode.Sha1, 6);
                loTotp.ComputeTotp(DateTime.Now);
                long lnTimeStepMatched = 0;
                bool lbVerify = loTotp.VerifyTotp(loCheckTotpData._nTotp.ToString("000000"), out lnTimeStepMatched, new VerificationWindow(2, 2));
                if (lbVerify)
                {
                    lsMessage += "<li>Successfully validated Totp code</li>";
                    lsMessage += "<li>Save is now activated</li>";
                    return this.Json(new { bResult = true, sMessage = lsMessage + "</ul>" });
                }
            }
        }
        catch (Exception loException)
        {
            lsMessage += "<li>" + Booking.Library.Classes.Utility.MakeExceptionMessage(true, loException, "\r\n", "_CheckTOTPCodeOnServer") + "</li>";
        }
        lsMessage += "<li>Unsuccessfully validated Totp code</li>";
        return this.Json(new { bResult = false, sMessage = lsMessage + "</ul>" });
    }
   
        public string MakeTOTPSecret()
        {
            string lsReturn = String.Empty;
            try
            {
                using (SHA1Managed loSha1 = new SHA1Managed())
                {
                    var loHash = loSha1.ComputeHash(Encoding.UTF8.GetBytes(this._gTOTPSecret.ToString()));
                    var loSb = new StringBuilder(loHash.Length * 2);
                    foreach (byte b in loHash)
                    {
                        loSb.Append(b.ToString("X2"));
                    }
                    lsReturn = loSb.ToString();
                }
            }
            catch (Exception loException)
            {
                Booking.Library.Classes.Utility.MakeExceptionMessage(true, loException, "\r\n", "Identity.MakeSHA1Secret");
            }
            return lsReturn;
        }