Oreo is Android's latest version release, and as with every release, there are always going to be kinks and issues that need to be ironed out in the following maintenance update. A considerable amount of users have been reporting that the Google Clock App is crashing. As a result of this, the moment a pre-set alarm goes off, the App Crashes and goes silent, causing many of these unsuspecting users to run late to work. You can find these over at Reddit. Google Clock App If you are running Android Oreo, you might want to check to make sure that your Alarm app is working as...
Source: http://www.gsmarena.com/psa_oreo_is_causing_google_alarm_clock_app_to_fail_for_some-news-27422.php