If ever you are maintaining a biometric attendance system and then you suddenly noticed that it is not functioning normally, or, if it is displaying a message "See gen log please" or something related its log file or log storage could be full.
Most cheap biometric attendance device uses a free or opensource software that you can commonly see in a biometric device (if you are in the Philippines).
Most of these devices are replying with a "thank you" whenever a successful login or logout is recorded and "try again" whenever a login or logout attempt is unsuccessful.
To fix the issue you need to delete all the attendance record or log on the biometric device.
Be sure to have a backup before doing so.