I just got a response from the email I sent...
----- The following addresses had permanent fatal errors -----
<questions~liteflour.com>
(reason: 551 Bad Recipient)

----- Transcript of session follows -----
... while talking to mail.liteflour.com.:
>>> RCPT To:<questions~liteflour.com>
<<< 551 Bad Recipient
550 5.1.1 <questions~liteflour.com>... User unknown

Hopefully, it's just that they don't have all the bugs out yet.