Because everything that's happened since this afternoon has gone poof with the dev board.
You might be able to retrieve by putting underdev02 in front of the url string after you click on your PM box, and then each message. Remove the www...the url should be underdev02.chronofhorse...blah blah blah.
So did they go through, or not? I replied to someone but I can't tell if she got it or not. The PM from her still shows as unopened/new no matter how many times I open it.
I imagine they've gone through, but to the dev board. If the recipient didn't check PMs prior to the switch back to the "real" board, and doesn't know how to access the dev board, they're not going to see the message (unless, maybe, they get email notifications--then they should see the message in the email, even if they can't access it on the board.)
I'd say your best shot of getting your message to the recipient is to resend. You can go pull your message from your sent file.