Unable to handle wrong otp in phone auth in flutter

[CSharper63]

Hello, I contact you becaue I use PhoneAuth to link it to mail account provider but I have NO way to check if the code is wrong. I try to use the token but it's always null, I try a shitty and unsecure method :

PhoneAuthCredential credential = PhoneAuthProvider.credential(
                                verificationId: verificationId,
                                smsCode: _codeController.text.trim());

UserCredential tmp = await FirebaseAuth.instance.signInWithCredential(credential);

if (tmp == null) {
Get.snackbar('app_error'.tr, 'wrong otp provided');
}

I try verification failed but not works.
So can someone help me ?? There is not much doc on web.