Sending
Resending to people who did not open
Giving a campaign a second chance: the new subject line, how long to wait, and warming up a sending domain.
Last updated October 14, 2026
Most people who do not open a campaign simply did not see it. Resend to non-openers sends the same email again, only to them, with a different subject line.
The settings
| Setting | What it does |
|---|---|
| Resend email subject line | The new subject. It should be different from the original — the same one in the same inbox looks like a mistake. |
| Wait before resending | How long after the original send. |
| Share of the list | What proportion of non-openers to send to. |
Two or three days is the usual wait: long enough that the first email has been missed rather than ignored, soon enough that the offer still stands.
Warming up a sending domain
A new sending domain has no reputation, and a first send of fifty thousand looks exactly like a spammer. Warm up this sending domain ramps the volume up over a period you choose, starting on the send date, so the receiving systems learn who you are gradually.
Use it for a genuinely new domain. An established one that already sends regularly does not need it.
A warm up only spreads out a campaign that will reach at least 1,000 people, and it counts only the people the campaign can actually email. Anyone who has unsubscribed, whose address has bounced, whose address is on a domain the list blocks, or who is outside the tribe a tribe's list is for, is left out before the count is taken, and someone on two of the campaign's lists is counted once. The campaign form shows this same number under Warm up this sending domain. A campaign that comes to fewer than 1,000 people is sent in one go on the send date, like any other campaign.
Every day's list is prepared on the send date, when the warm up starts, and each person is checked again as they are added to it. If nobody on a day can still be emailed by then, that day is skipped rather than sent, and the campaign page counts only the days that go out.