Update: As the mail server has been stable for a while now, this can be considered fixed.
We are currently having some issues in receiving mail sent to addresses at simplemachines.org. Our team is working on finding the cause and getting it corrected.
Messages are not being rejected and should be held by outside servers until they can get through to us. While this means that we should get all messages eventually, it does mean that there could be a very long delay before we see them.
For urgent issues, along with sending an e-mail, please try to contact one of the project managers by PM, IM, or by posting a topic in the appropriate board.
This message will be updated once the problem has been resolved.