What are ‘Unknowns’? Am I charged for them?

We guarantee up to 99% accuracy for our verifications. When a verification is run, the results obtained depend on the responses we get from the email providers.

TheChecker will attempt to connect with the server several times, but an ESP may block the requests, which means we never get a response. In these cases, the result will show as "Unknown."

The answer to the second question is no. If you had emails marked as "Unknown" after any verification, those credits are automatically refunded to your account balance so that you can try again later for free.

Why am I getting a high amount of unknowns? What should I do with them?

The "Unknown" results usually happen with small email providers, such as universities (.edu domains), Government mailboxes, and other small email providers that take too long to respond to our requests - so the connection is aborted.

We are continually working on improvements so that our clients have the least amount of unknowns. Due to our high-speed verification, we do not get a quick enough response from some email providers.

It is worth mentioning that: there is always a trade-off between speed and the least amount of unknowns. That's the balance that we're continually looking to improve. Many verifiers may not mark emails as unknown - but they may end up giving false positives.

If you have a lot of unknown emails and don't know what to do, we recommend keeping them separate and trying again at another time, in high precision mode. By enabling this, the verification time will considerably increase, but it will provide you with the very least amount of 'Unknown' results.
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