Choose which senders a campaign uses

How to do it

1. Open Settings → Mailboxes. With nothing chosen you'll see "No specific senders chosen — this campaign rotates across all N healthy senders."
2. Click Choose mailboxes. Filter with All / Selected / Actively sending / Warming up / Idle, tick the senders you want (or "Select all shown"), and click Done. The choice saves immediately.
3. Remove a sender from the list with its Remove button.
4. Watch the "emails/day combined capacity" figure — the sum of the chosen senders' daily caps.

Good to know

• Only active (connected, healthy) senders are offered. Each row shows the provider and its daily cap, plus Sending (sent in the last 7 days) and Warmup badges.
• Leave the selection empty to use every healthy sender — the default and the recommended setup for rotation.
• If every mailbox the campaign picked is deleted (or moved to another workspace), it does not fall back to every healthy sender. A sending campaign is paused, and a red alert on its pages says which mailboxes went and when. This tab then shows the alert with Choose mailboxes, reads "No mailbox picked" (the picker shows "None picked · 0/day"), and the campaign can't launch or resume until at least one is picked — picking one clears the alert. The alert's link opens Settings straight on this tab.
• Sends rotate across the allowed senders, least-used first, one email per sender at a time, respecting each sender's daily cap and send gap.
• Follow-ups to a person go from the same mailbox that emailed them before. If that mailbox is at its daily limit the follow-up waits for it rather than switching; it only moves to another sender if that mailbox is disconnected, removed from the campaign or deleted.
• If a provider refuses for the day ("Daily user sending limit exceeded"), that mailbox is rested until tomorrow and other senders carry on.
• Subsequences created later inherit the parent campaign's sender selection at the moment they are created. One created while the parent has no mailbox left carries the same alert and can't be switched on until a mailbox is picked in its own Settings → Mailboxes.