Why do my emails trickle out?
Learn how ColdMerge spaces sends inside campaign windows and what happens when a window closes.
2 min read
A send budget limits how many messages a mailbox may send. Pacing controls when those messages leave. ColdMerge spreads sends through the available window instead of releasing them in one burst.
How pacing works
Section titled “How pacing works”ColdMerge considers the work still queued, the time left in the window, and the mailbox’s remaining budget. It then adds variation so messages do not leave at perfectly even intervals.
| Rule | Effect |
|---|---|
| Minimum gap | Sends from one mailbox stay at least 10 seconds apart |
| Pace ceiling | A nearly finished campaign does not stretch a few sends across the whole day |
| Variation | Each gap changes around the calculated pace |
The send budget is a ceiling, not a target. If the window is too short to use the whole budget without breaking the minimum gap, the remaining work waits.
Why a sending window exists
Section titled “Why a sending window exists”A sending window defines hours, weekdays, and a timezone for a campaign. New campaigns copy the organization’s default window.
A scheduled start is the earliest time the campaign may begin. The window still applies. A campaign scheduled for a closed day waits until the next opening.
To change the default, see Set your default sending window.
What happens when the window closes
Section titled “What happens when the window closes”Sending pauses and continues when the window next opens. A campaign that does not finish today carries its remaining recipients into the next sending day.
The worker checks for newly available work on a schedule, so sending may resume a few minutes after the opening time rather than at the exact second.
Why the completion time is an estimate
Section titled “Why the completion time is an estimate”The estimate changes as mailbox budgets refill, replies stop follow-ups, new follow-ups become due, or a mailbox becomes unavailable. Days outside the campaign window are not sending days.
ColdMerge also reserves room for possible follow-ups before it starts a new conversation. A new first send waits when its possible follow-ups would crowd out existing work. Due follow-ups keep priority. You can still see each mailbox’s current send budget on Accounts.
When no mailbox can send, ColdMerge explains the blocker instead of showing a completion estimate.
When one mailbox stops
Section titled “When one mailbox stops”Other campaign mailboxes can continue with contacts that have not yet been assigned. Follow-ups already bound to the unavailable mailbox wait so their Gmail thread and sender stay consistent.
| Cause | What happens |
|---|---|
| Temporary Gmail rate limit | ColdMerge waits, then tries that mailbox again |
| Gmail quota reached | The mailbox waits for later capacity |
| Workspace administrator block | The mailbox is retried periodically until the administrator allows the app |
| Reconnection required | Sending waits until you reconnect the mailbox |
See Connect and manage mailboxes for mailbox problems.