TL;DR
A new campaign can take up to 24 hours to send its first emails, and it only sends on its sending days and hours.
Every inbox ramps up from 1 to 25 emails a day over its first 7 sending days, so low volume in the first week is normal.
Campaigns that share inboxes share those inboxes' daily limits, and follow-ups count toward the same limit.
A campaign with no leads left to start, or a failed payment, sends less or nothing.
If none of this explains it, message us with the campaign name. Don't re-upload your list.
When you'd use this
Use this when a campaign hasn't sent anything yet, or sends far fewer than 25 emails per inbox a day. A Bundle sends about 1,000 emails a day at full volume (40 inboxes at 25 a day each), but sending is paced on purpose to protect your inboxes.
What to check
Are your inboxes Ready? On the Inboxes page, the Warmup Status column shows Ready when an inbox can send. Branded inboxes warm up for 14 days first. Don't launch on inboxes that are still warming. If a campaign is already live on them, pause it and resume when they show Ready. See My inboxes say 0/1. When will I start sending?.
Are your inboxes still ramping up? Branded inboxes take up to 72 hours to set up, then warm up for 14 days (about 2 to 3 weeks from signup). Pre-warmed inboxes skip warmup. After that, every inbox ramps up: it starts at 1 email a day and adds 4 on each weekday it sends in a live campaign (1, 5, 9, 13, 17, 21, 25), so it reaches 25 a day on its 7th sending day, about 9 calendar days. The Emails Sent column on the Inboxes page shows emails sent today out of each inbox's daily limit, for example 2/25. With 40 inboxes, day one is about 40 emails, not 1,000.
Is the campaign inside its schedule? In Campaign Setup, check the time zone, the sending days (Monday to Friday by default) and the start and end time. Nothing sends outside them.
Did you launch less than 24 hours ago? A new campaign can take up to 24 hours to start sending.
Are the inboxes selected, and shared with other campaigns? In Who is sending this campaign?, check the inboxes and their Campaign Used count. Each inbox has one daily limit for all its campaigns, covering first emails and follow-ups together.
Does the campaign have leads left? The ring next to each campaign on the Campaign page shows how many leads haven't started. "No leads left to start" means only follow-ups remain. Follow-ups wait for the delay you set, and a lead who replies gets no more emails.
Did a payment fail? Campaigns pause when a payment fails. Resume them once the payment goes through. See How does ListKit billing work?.
Did you lower an inbox's daily limit today? If the new limit is below what the inbox already sent today, it stops until tomorrow.
Still stuck? Message us with the campaign name and roughly when sending stopped. Send us a message in the app. Our support team replies Monday to Friday, 9am to 5pm ET, usually within 2 hours. Messages sent outside those hours are answered the next business day.
Expected outcome
You can tell normal pacing (warmup, ramp-up, schedule, shared inboxes, follow-up delays) from a real problem, and you know when your campaign will reach full volume.
FAQ
My campaign was supposed to start at 11 today. Why have no emails been sent out?
There's no start time. A campaign starts when you publish it, within its sending days and hours, and can take up to 24 hours to send its first emails.
My daily sends are 12 to 13 out of 25. Why is this so low?
The count shows emails sent today out of the daily limit, and sending is spread across your sending window, so it rises through the day. It also stays lower if the inbox is shared with other campaigns, the campaign has few new leads left, or follow-ups are waiting for their delay.
Why did this only send 440 emails when all inboxes are set to send 25?
Usually a mix of ramp-up, the sending window, inboxes shared with other campaigns, and follow-ups waiting for their delay. Work through the checklist above.
I have 6,000 leads on a 1,000 a day Bundle. Why did only 40 go out on day one?
Your inboxes are ramping up. Day one is 1 email per inbox. Volume climbs each sending day until every inbox reaches 25.
Should I pause a campaign before starting another one?
No. Campaigns can run at the same time. If they use the same inboxes, they share those inboxes' daily limits.
Why are all my campaigns paused?
A failed payment pauses campaigns. Check your Billing page, then resume your campaigns once the payment goes through. If that's not it, message us.
Should I re-upload my leads to get them sending?
No. Re-uploading leads that are already in a campaign can email the same people twice. Message us instead.