An error occurred while processing alert notifications. Data is Null. (4310833)

Email alert notifications are no longer being delivered.

Application event log shows the following error: An error occurred while processing alert notifications. The notification service will retry in 2 minutes. Data is Null.

1. Run the (AA) Active Administrator Configuration Wizard and create a new Active Administrator database.
2. Run the AA Database Migration Tool to export any custom email alerts and custom reports from the original database and import them into the new database.
3. Launch the Active Administrator Console and re-install the audit agents within Auditing & Alerting | Agents.