Once a campaign is launched, mailzy:
- sends only inside the days and hours you chose, in the campaign's time zone (or each lead's own, if you switch that on);
- spreads the work across your mailboxes: each new lead goes from your healthiest mailbox that has sent least today;
- keeps each lead's follow-ups in the same email thread, from the same mailbox;
- stops the sequence for anyone who replies;
- spreads each mailbox's day evenly across your sending hours (on for new campaigns, under Settings, Pace), so 30 a day in a 9-to-5 window go out about every 16 minutes.
New mailboxes start slowly
A mailbox starts at 5 campaign emails a day and adds 5 for each day it sends, up to its limit, so its volume never jumps. Launch names any mailbox still ramping up, so a slow first week is expected.
Mailbox health
Each mailbox is healthy, on watch or at risk, from its bounces, spam placement, warm-up results and other signals. A mailbox on watch sends at half speed; one at risk rests from campaigns and comes back gradually once it recovers. Its new leads move to your other mailboxes.
When a campaign slows or pauses by itself
- Bounce Guard: pauses the campaign if more than 5% of its emails bounce, once 200 or more have gone out.
- Opt-outs: if unsubscribes and "remove me" replies pass 2% of its last 200 emails, it slows to half its pace and tells you; at 4% it pauses. It speeds up again by itself, a step a day, as fewer people opt out.
mailzy may also pause sending if a campaign's bounces or unsubscribes are far above normal, to protect everyone's deliverability. You'll see the reason; contact support to resume.