How Do I Permanently Stop or Drop Queued Mail?

The admin bounce (kcli bounce) is the tool for dropping queued mail in an emergency, and it is transient: it applies only for the duration you specify and is forgotten after a restart. It is an operator "stop the bleeding" command, not a permanent policy.

Drop mail now

# Drop everything (irreversible)
$ kcli bounce --everything --reason 'purging all queues'

# Drop a specific destination domain
$ kcli bounce --domain yahoo.com --reason 'bad send'

# Drop a campaign
$ kcli bounce --campaign 'Back to school' --reason 'bad send'

A bounce stays active for its --duration (the default is 5 minutes), so it catches both currently-queued messages and any that arrive during that window. Set a duration at least as long as your retry interval if you want to keep catching retries.

Make it take effect immediately

Bounced messages keep their existing next-attempt time unless you flush them. Follow the bounce with a rebind to apply it right away:

$ kcli rebind --everything --always-flush

Cancelling scheduled mail

There is no separate "unschedule" command. To cancel messages scheduled with msg:set_scheduling(), use an admin bounce scoped to the matching domain, campaign, or tenant. It operates on the Scheduled Queue as well.

Warning

kcli bounce matches on the recipient domain/campaign/tenant. To drop mail by sender domain, match msg:sender().domain in a rebind_message handler and run kcli rebind.

Making it permanent

Because the admin bounce evaporates on restart, encode any lasting "never send this" rule in your Lua policy (reject at reception, or inside a rebind_message handler) rather than relying on a standing bounce.