I have the same issue now for the 2nd time.
I can sync with GE with my iMac but with the GC on the iPhone the sync is "frozen". I had to do a reset with complete deletion of the settings and the data. After setup and reconnection with GE and GC it works again.
BTW. The steps, heart rate, ... is synced but not the activities.
And i have the same issue after last android app update!
I reset watch (full with data reset) in im still unable reconnect to phone.
App sees watch, but is unable to complete setup.
On iOS I have the same issue every now and then. I then do the following:
1: Force quit the GCM app
2: Go to iOS settings and disable Bluetooth / enable Bluetooth
3: Open the GCM app again, and everything is Ok again - until it happens again.
I use Android phone.
But finally fixed coonectivity problem.
After trying everything (cleared everything and lost ~ week of my activity data :/) to morrow i deleted every bluetooth paired device from phone bt seetings. And it worked! I was able to connect watch again!