Mail Queue

Emails > Queue (/emails/queue) is Postfix's queue: everything the mail server has not managed to deliver yet.

The queue is one flat list. On a server with a compromised account it is tens of thousands of entries with a single sender, so the page can narrow it by sender or recipient rather than leaving you with only "retry everything" and "delete everything".

Per message you can read it (/emails/queue/message/<queue_id>), hold it, release it, requeue it, or delete it. The same actions can be applied to a selection in bulk.

Queue ids are validated before they reach postsuper, postqueue or postcat. Postfix takes ALL as a queue id, so an unchecked value here would be one request away from deleting the whole queue. If part of a selection is dropped by that check, the page tells you rather than quietly acting on less than you asked for.