Hello, Looking at https://github.com/egulias/EmailValidator/blob/515346048d25037c253c0731b136866897d1f1c3/src/Validation/DNSCheckValidation.php#L171 and https://github.com/egulias/EmailValidator/blob/515346048d25037c253c0731b136866897d1f1c3/src/Validation/DNSCheckValidation.php#L197 condition " if (empty($this->mxRecords))" can never been achieved when DNSRecord contains no MX. By consequence, if you test a domain with no MX record at all, validation returns valid.