After upgrading the Symantec Endpoint Protection Manager (SEPM) to 14.3 RU7 you start receiving email notifications that "LiveUpdate failed". These emails were not received prior to the upgrade.
Release : 14.3 RU7
14.3 RU7 enabled the System Event notification condition, named "Server Error", by default. In prior versions this could be manually enabled but was not enabled by default. Unless that had been enabled manually prior, you would not have received email notifications of LiveUpdate failing.
These new notifications are by design to notify you of LiveUpdate failures that may need to be investigated. If you do not wish to receive these emails, you can delete the "Server Error" notification condition in the SEPM located in Monitors -> Notifications -> Notification Conditions.