A: Sometimes when verifying emails, a small portion may return as “Unknown.”
This usually happens when the receiving mail server doesn’t respond in time or has strict anti-spam filters that block verification attempts.

While many of these emails turn out to be invalid, we can’t confirm with 100% certainty at the time of checking — which is why they’re marked as “Unknown” instead of giving you a wrong result.

This approach helps ensure accuracy and protects you from false positives.