Is your Facebook message to your friend being sent but not delivered? First you need to understand what those terms mean. "Sent" means that your message successfully made it from your device to the Facebook message server. "Delivered" means that the message successfully made it from the Facebook server to the other person's device. If the person's device is turned off, or if it's not logged in to Facebook at the time, it will be delivered once they log in. But there is more.... read below...