Recording without a connection: how it works
The track is recorded on the device and reaches the server at the first sign of network.
Recording is built offline first: GPS points are saved in the phone’s memory, and recording needs no internet at all. As soon as the network appears, the track uploads itself to the server.
While a track is waiting for a connection, it shows at the top of the “My activity” screen: “ride waiting to upload”. The “Send” button is there too, for when you are back online and the track still hasn’t gone. If the server didn’t accept a recording, it is shown there as well, with the reason: you can send it again, save it as a GPX file, or delete it from the phone.
A map for navigating without a connection is a separate matter: download the area’s offline pack in advance (the offline maps section; included in the ENDURO subscription). The area where you are recording gets cached on the free plan too.