Device logs should be sent to a centralized device for log collection, retention, and reporting. This could be a SIEM. syslog device, FortiAnalyzer, FortiManager, etc. Centralized logging allows for more reliable log retention and more enriched log data for review and reporting.
Solution
Configure a remote server for logs to be sent to: 1. Go to Log & Report > Log Settings. 2. Under "Syslog logging" configure a remote server to send logs to.