iOS 11.0
GCM 3.22.1.5
Forerunner 230 7.5 (bdd586f)
I have factory reset the watch, and reinstalled GCM, rebooted the iPhone. Still, when I start the pairing process, GCM says "Device Found : Do you want to pair with Forerunner 230?", I select "Yes" (the FR230 is showing "Ready to Pair"), GCM shows "Connecting", and then after 30s or so, "Pairing Failed : Unable to pair your Garmin device.".
Any suggestions? This worked fine in iOS 10.3.3.