Before you send an official launch email to your members, outgoing emails from your SilkStart website are turned off - only administrators of your website will receive email notifications.
This is a preventative measure to ensure that notifications are not sent to unsuspecting members from a website that they may not recognize. This lets you continue to set up your website after your members are imported, and not worry about accidental email notifications.
When you are ready to launch and start engaging your members, your account manager can help you ensure that outgoing emails are turned on. For more details on launching your SilkStart site, see this article.