If, after recording an activity on the iOS app, you are unable to sync the activity give the following a try:
- Log out and then back into the Strava app.
- Turn your phone off and then back on again
- Make sure you are in an area with good data coverage or, even better, connect via WiFi and tap on the ride to try again.
- If this doesn't work, the activity may be corrupt and will be unable to upload. In this case, you'll need to remove the failed upload. Pull down on the 'me' feed slightly (but not all the way) as if you were going to refresh. You should see 'You have one new activity.' Click on this and you will be taken to the 'Unsynced Activities' page. Swipe the activity to reveal the delete button.