What happens when a campaign send is interrupted
A campaign send that stops halfway should pick up where it stopped: the people who already got the email are skipped and only the rest receive it. Email Digit keeps a record of every recipient it sends to, restarts a stalled send on its own, stops after three failed restarts and tells you, and lets you resume once the cause is fixed, again sending only to the remainder.
Why sends get interrupted
A campaign to a few thousand people is not one action. It is thousands of individual sends spread over minutes, sometimes longer, and a lot can happen in that time: a server restarts for a deployment, a process crashes, the sending service has a brief outage, a daily limit is reached.
Each interruption can go wrong in one of two ways:
- Sent twice. The send restarts from the top, and everyone who already received it gets it again. To the reader, that looks careless.
- Half sent, looks finished. The send stops, nothing restarts it, and the campaign sits in a state that looks like success. Half your audience never hears about the sale, and you find out from the numbers a week later, if at all.
The second is worse, because nobody knows to fix it.
What a resumable send needs
Whatever tool you use, these are the questions worth asking:
- Is a record written for each recipient as the send goes, not only at the end?
- Does a restart check those records and skip people already sent to?
- Does something notice a send that has stopped making progress?
- Is there a limit on automatic retries, so a send that fails the same way every time stops?
- When it stops, is a person told, with the reason?
How Email Digit handles an interrupted send
Every recipient a campaign sends to gets a send record, with its status. Progress is saved as the send goes, every 200 recipients. A campaign that has not made progress for 15 minutes is treated as interrupted and restarted automatically, and the restarted run skips everyone who already has a record. Its totals start from the earlier records, so the report still adds up across the restart.
An example: a campaign to 2,000 people stops after 1,200 sends because the server restarted. Once it has gone 15 minutes without progress it is picked up again, the 1,200 are skipped, and the other 800 receive it.
Three restarts, then it stops and tells you
An automatic restart covers a real one-off: a redeploy, a brief provider problem. A send that keeps failing has a cause, and retrying it forever would only hide that. So after three restarts the campaign is marked failed, you get a notification, and the campaign report shows the last error.
Resume once it is fixed
On the report of a failed campaign, Resume puts it back in the queue. The confirmation tells you how many sends remain, and the same rule applies: everyone who already received the email is skipped. A campaign that was halted because the account was paused works the same way, and it is not resumed automatically when the account is restored. A campaign that stopped days ago may no longer be the right message, so that decision stays with you.
The edges, stated plainly
| Situation | What happens |
|---|---|
| The send stalls between saves | Restarted after 15 minutes; only recipients without a record get it |
| The process stops hard in the middle of a group of 200 | Sends in that unsaved group have no record yet, so some people in that one group can receive the email a second time |
| One recipient’s send was rejected | It has a failed record, so a resume does not retry it; it shows as failed in the report and the export |
| Three restarts fail | Marked failed, you are notified, last error shown; Resume when fixed |
The second row is the honest limit of saving progress in groups rather than after every single send. It bounds a repeat to part of one group of 200, rather than the whole list.
Every individual send is checked against your do-not-send list as it goes out, so someone who unsubscribed while the send was stalled is not sent the email when it resumes.
How to check a campaign after an interruption
- Open the campaign report and compare sent and failed against the audience you approved.
- If it is marked failed, read the last error before resuming; fix the cause first.
- Export the campaign CSV. It has one row per recipient with their status, so you can see exactly who received it and who did not.
A duplicate campaign looks careless and a half-sent one that looks finished is worse. Both are the sender’s problem to solve, which is why it is handled in the sending itself. See how campaigns work in Email Digit, or start a 14-day trial.