LandInsight GO isn't currently optimised for offline use. You can still view previously saved sites when offline, but without full information or updates until you're back within range of a signal.
On the map, address details, as well as ownership and site size information can't load without a data connection; without access to the web we can't save your sites either.
You might find that GO takes a moment to return to normal once you've found a connection, or when you have a very limited connection - this is to prevent issues with sites not loading or saving properly in those initial uncertain seconds before data begins to flood into your device once more.