You shouldn’t use Clue Conceive without being connected to the internet. If you’re offline, you can still open the app and view your past tracked data in the Analysis Tab, but your Cycle View and Calendar View will show data and predictions which are not up to date.
If you’re not connected to the internet, you’ll see this message on a banner: “Looks like you’re offline. Go online to see updated predictions.” If you see this message, get back online as soon as you can to continue getting accurate predictions.