So I just picked up a Garmin and cannot get it to communicate with Garmin Connect. It shows as connected on my IPhone and Garmin unit. In advance you should that I recycled the connection, restarted phone and gps, and deleted the GC app and reinstalled it.
Have you hard reset GPS to factory? Garmin firmware sucked in my experience. The latest 510 firmware killed mine and had to revert back to an old one to make it work a little longer until Wahoo.