Why did my Brevo campaign go out on a different day than I planned?
The Brevo help pages give 4 common reasons. The first to rule out: In an A/B test, a sample gets the two versions first and the winning version goes to everyone else when the test ends, so most of a campaign's sends can land on a later day.
Is it broken, or just quiet?
A number can fall because fewer people came, or because something stopped counting them. Below are the causes the Brevo help pages give, and how to check each one yourself.
What causes it?
In an A/B test, a sample gets the two versions first and the winning version goes to everyone else when the test ends, so most of a campaign's sends can land on a later day.
In the Brevo help:
The winning version will be sent at the end of the test.
Create an email campaign, read 2026-11-12.When a campaign is set to send at the best time, Brevo keeps the date you picked and chooses the time itself, so sends can come at a different hour than the one you set.
In the Brevo help:
If sendAtBestTime is set to true, your campaign will be sent according to the date passed (ignoring the time part).
Create an email campaign, read 2026-11-12.Brevo advises including the time zone with a scheduled send time; without it, a campaign can go out at a different hour, or on a different day, than you meant.
In the Brevo help:
Prefer to pass your timezone in date-time format for accurate result.
Create an email campaign, read 2026-11-12.When a dedicated IP is being warmed up, sending is spread across days with a daily amount, so one campaign's sends can land over several days.
In the Brevo help:
If you want to send the same number of emails every day, set the daily increase value to 0%.
Create an email campaign, read 2026-11-12.
How do I check it myself?
Compare the campaign's scheduled time with your own time zone, since Brevo records it in UTC and the UTC date can differ from the date on your clock.
In the Brevo help:
UTC date-time on which campaign is scheduled (YYYY-MM-DDTHH:mm:ss.SSSZ)
Get an email campaign report, read 2026-11-12.Check whether the campaign was set to send at the best time, since that lets Brevo pick the hour.
In the Brevo help:
It is true if you have chosen to send your campaign at best time, otherwise it is false
Get an email campaign report, read 2026-11-12.For an A/B test, check how long the test was set to run, since the winning version is sent only when it ends.
In the Brevo help:
The duration of the test in hours at the end of which the winning version will be sent.
Get an email campaign report, read 2026-11-12.
How would I know the day it starts?
- Feder reads the campaign emails Brevo sent each day and compares each day with your own history.
- If sends go quiet or move outside your usual range, Feder tells you.
Some numbers are too quiet to judge daily, such as a form filled in a few times a week. Until there is enough of your own history to judge a change, Feder says it is still learning and scores nothing, rather than guessing.
See what Feder reads from Brevo, which feeds Reach. Feder only reads. It never changes anything in Brevo.
What else goes wrong with these numbers?
- Why did my Brevo email campaigns stop sending?Brevo
- Why are fewer of my contacts getting my Brevo campaigns?Brevo
- Why did Google Analytics stop collecting data?Google Analytics
- Why aren't my key events showing in Google Analytics?Google Analytics
- Why does Google Analytics show (not set)?Google Analytics
See every question.
Where do these answers come from?
Every cause and check on this page comes from the Brevo help pages, quoted above with the date we read them. Last reviewed 2026-11-12. We read them again by 2027-11-12. If one changes, this page changes or comes down.