Problem
Antispam quarantine reports are delayed.
Solution
In most cases, this is caused by an excessive number of quarantine accounts.
When an email is accepted for a recipient and identified as spam, a quarantine account is automatically created in FortiMail.
Check that these quarantine accounts are valid, as netbots and spam harvest scans can cause the creation of a large number of false accounts.
There are options to manage quarantine accounts in FortiMail. These options are available under Mail Settings > Domains (not in server mode).
• Enable Recipient Address Verification to stop invalid account creation with SMTP or LDAP authentication (Note that LDAP cache should be enabled).
• Remove invalid accounts by enabling Automatic Removal of Invalid Quarantine Accounts.
Recipient validation is a clean solution with a performance cost on SMTP or LDAP services. Its another disadvantage is that it also results in informing the outside whether the accounts are valid or not.
The automatic clearance of accounts is started once per day at 4:00 AM by default, but can be modified by the following CLI command:
config antispam settings
set system option backend_verify <hh:mm:ss>
end
where hh is the hour according to a 24-hour clock, mm is the minute, and ss is the second.