FrontlineSMS and FrontlineCloud automatically process messages when the connections to a device, web aggregator service, or SMSSync are active. If any of these connections are disconnected for a period of time, incoming messages will be held by your device or service until the connection is re-established. At that time, the applications will pick the messages up. FrontlineSMS and FrontlineCloud will then trigger any actions of you have set via activities or keywords. No messages should be lost, unless you manually delete them from a device, like a cell phone, before connecting it to the application.
*Please note: If you are using FrontlineCloud and your account expires, your connections will be disabled and you will not receive messages. If your account is reinstated, you may not receive messages that were sent in the interim.