An SMS message can have four statuses. They will be presented in the desktop app and the mobile app, along with the following "explainer" messages:
Sent: The message has been sent, but the contact's SMS provider did not confirm delivery.
Delivered: The message has been sent, and the contact's SMS provider has confirmed delivery.
Undelivered: We attempted to send this messages and the contact’s SMS provider responded that this messages could not be delivered.
Failed: Something unexpected happened and your message could not be sent. The UpLaunch team has been notified, and we will look into it. If you continue to have issue please contact support.