If you get this error, you may want to try to reset your alarm unit. In order to do so, follow the steps below:

1) Turn your alarm off and then on again. Wait for a period of around 10 seconds;

2) Insert the reset code (88008800);

3) Press the "Disarm" button for 5 seconds, until the alarm beeps twice.

You have successfully reset your alarm. Now go to the app on your smartphone and try again.