Hyphenated domains are marked invalid

[admrply]

Any domain with a hyphen is marked as invalid, for example: [email protected]

[vv12131415]

@admrply not any, for example [email protected] this is valid
But still there is an issue.
Also [email protected] (that the real domain, check it in whois)

[jeffreykemp]

foo-bar.com is not (currently) a valid domain; it certainly is not publishing any MX records. So it should not be marked as valid.

[RyanPaiva56]

We can reproduce this as well in production with a [email protected] email address. Sending an email to them (over gmail) works, but validating the email using this API fails validation.