phone verification does not work for more than one user

Hello, I am using phone authentication for my project. I am sending the code using createPhoneToken and verify the code with updatePhoneSession. It verifies correctly when there is only one user in the database but after the first user is verified, the second user still gets the SMS code but the verification code cannot be verified. Here is my code, could you please indicate what I am doing wrong. Thank you for your help.

Future<String> sendPhoneVerificationCode(String phone) async { try { final token = await _account.createPhoneToken( userId: ID.unique(), phone: phone, ); return token.userId; } catch (e) { rethrow; } }

Future<models.Session> verifyPhoneCode(String userId, String code) async { try { final session = await _account.updatePhoneSession( userId: userId, secret: code, ); return session; } catch (e) { rethrow; } }