How to match the code with a flutter library?

Hello everyone,
I am using the library dart-otp in a flutter app that generate the code and i need to validate this code in c# but i couldn't validate this code nor generate the same code from the two libraries.
The code in flutter/dart is

var now = DateTime.now();
      now = DateTime(2023, 04, 26, 10, 10, 10);

      var code = OTP.generateTOTPCodeString(
          'DDXFM42476476545', now.millisecondsSinceEpoch,
          algorithm: Algorithm.SHA256, isGoogle: false);

      print(code);  // Out 667099

In C# the code is

string skey = "DDXFM42476476545";

            var  now = new DateTime(2023, 04, 26, 10, 10, 10);
            var totp = new Totp(Base32Encoding.ToBytes(skey),30,OtpHashMode.Sha256);
            var code = totp.ComputeTotp(now);
 //code = 734057

Can anyone help to figure this difference?

No repository file or test is named. Start by reproducing the two examples and reading the Totp.ComputeTotp entry point, then compare its inputs with dart-otp's generateTOTPCodeString inputs. Done means identifying the cause of the differing codes and documenting or correcting the behavior if it is a library defect.