My Fenix3 failed to upload an activity this morning. it is not sync through GC mobile. I tried to re-pair through Bluetooth (iphone 5S) and I receive an error saying Cannot pair. Invalid unit ID.(in turkish) . It has been working fine. It is really annoying that every update in Garmin is trouble.
920XT Having sycn isssues via BT/GC Software Version 6.10
I have a similar issue of syncing via BT using GC after updating Software version to 6.10. I managed to get syncing to work on direct USB connection and via Wifi after fixing FIT file.
I hear something similar is happening on Fenix 3. Any idea how to fix this BT sync?