Once your activity is complete and you choose to save your file, it will automatically be queued up for syncing the next time you have a stable data connection.
If you have an intermittent or unreliable data connection, the app will not be able to properly sync. Not to worry, though! Your data will remain intact on your device, and the sync will resume the next time you open the AllTrails app within range of a stable data connection.
If you are experiencing sync issues between your AllTrails app and your AllTrails web account, be sure to check that you are using the same email address to log in to the app for both.