Sync watch to phone failed, activity now missing
I usually sync my watch (TomTom Adventurer) through my laptop. This evening though I tried to pair the watch with the mobile app and sync from there.
It did show it was syncing but then the activity couldn't be found anywhere, so the sync failed somehow.
A few minutes later I retried again on the phone (while still out) but it found nothing to sync.
Now I've just come back home and connected the watch to the laptop but apparently it finds nothing to sync there too.
Have I lost my activity for good? If so, why?
It was quite a long one, I don't know if that is the problem. If it is, it shoud be noted somewhere that syncs may fail and then be unrecoverable.
Thanks for any help.