Why did my MillionVerifier API checks stop coming through?
The MillionVerifier help pages give 4 common reasons. The first to rule out: If the address your system calls from is blocked in the account's own settings, its checks can be refused.
What causes it?
If the address your system calls from is blocked in the account's own settings, its checks can be refused.
In the MillionVerifier help:
In your settings, the IP address you are trying to make the call from is blocked.
Why Is My IP Blocked? - MillionVerifier Help Pages, read 2026-11-12.A call made with an API key that does not exist on the account can be refused.
In the MillionVerifier help:
You are trying to make the API call with a non-existing API Key.
Why Is My IP Blocked? - MillionVerifier Help Pages, read 2026-11-12.An API key that has been turned off cannot be used until it is turned back on, so checks sent with it can stop.
In the MillionVerifier help:
If the slider is not green, the API Key is not active, and you cannot use it.
Manage API keys - MillionVerifier Help Pages, read 2026-11-12.Checks depend on how quickly each address's mail server answers, so some can take much longer than usual.
In the MillionVerifier help:
Unfortunately, some mail servers are not that fast, and email address verification can take more than 20 seconds.
API Speed - MillionVerifier Help Pages, read 2026-11-12.
How do I check it myself?
Look at how long each check took in the API response to tell slow mail servers apart from refused calls.
In the MillionVerifier help:
In our API response, you can see how long the email verification took in milliseconds.
API Speed - MillionVerifier Help Pages, read 2026-11-12.When reading the account's API usage, remember calls are grouped by the minute, so one entry can stand for several checks.
In the MillionVerifier help:
If you see that an API call costs 2,3,4...etc. credits every minute, it is because API calls are logged every 1 minute.
Real-Time API - MillionVerifier Help Pages, read 2026-11-12.
How does MillionVerifier work with Feder?
- Connect MillionVerifier to Feder and it joins your Interest apps.
- When you connect MillionVerifier, Feder checks the connection straight away and shows Connected only when that check passes. If a reading cannot be taken later, Feder shows it as not read, never as zero.
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 whether you can trust the numbers in MillionVerifier, one of your Interest apps. Feder only reads. It never changes anything in MillionVerifier.
What else goes wrong with these numbers?
- Why did fewer emails come back as good in MillionVerifier?MillionVerifier
- Why is my MillionVerifier file stuck near the end with no results yet?MillionVerifier
- 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 MillionVerifier 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.