As a rule, emails are directly delivered to the destination server.
However, if the delivery attempt to the destination server is returning a temporary failure, all emails sent to known valid recipients are queued locally on the filtering servers for delivery retry.
Emails that have been permanently rejected by the destination server with a 5xx error code, will NOT be queued and are rejected by the systems.
If the destination mail server acts as a catch-all for the domain, no recipients will be cached and therefore email will only be queued if the valid recipients have been explicitly set as Local Recipient in the SpamExperts control panel.
In such instance, a recipient is not cached as valid, the message will be temporarily rejected and queued at the sender instead of on the filtering server (unless Local Recipients is enabled).
Customers with active SpamExperts service account can access the email queue from the web interface, from which you can also manually retry delivery of a queued message.
