Problem
Mail queues do not appear on the HA backup unit.
Solution
In order to display queue content in the backup unit, mail data must be synchronized from the primary unit. If the Backup MTA queue directories option is disabled, mail queues will not be synchronized. You can enable MTA spool synchronization to view the mail queues from either the backup unit or the primary unit.
| Synchronization of MTA spool directories can result in decreased performance, and may not let you to view all email in the mail queues, as mail queue content can change more rapidly than synchronization occurs. |