It may be that the Guardian camera appears 'Offline' in the Smartwares View app as soon as you are out of range of your own network. This is due to the setting UPnP (Universal Plug & Play) not being enabled in the settings of your router.
In order to enable UPnP, please log in to your router, go to its settings, find UPnP and enable it. If you are unsure how to do so, please check the manual of your router or contact your internet service provider (USP) for support.