Before you can clearly define an abnormal operation, you need to know what the normal operating status is. You can create a repository of this baseline information by keeping logs, and by regularly running information gathering commands and saving the output. When there is a problem, this regular operation data helps you determine what has changed.
It is a good idea to back up the FortiMail unit's configuration regularly. If you accidently change something, the backup can help you restore normal operation quickly and easily. Backups also can aid in troubleshooting.