Wouldn't it be nice to have some sort of direct response from Garmin Support on this. We spend time trying to unravel the bugs whilst they watch on in silence! This isn't support.
I finally resolved the problem, at least it works on the first attempt as it was before the recent updates. In Garmin Connect go to More (right bottom) - Settings - App Authorization - Localization - turn on. After this change Live track worked as before.
My other settings in IOS for the app Connect : Access to position when used, On for contacts and for updates in background. These have never been changed.
Hope it will be useful.
I too have had issues with LiveTrack for weeks, then I found this thread and decided to investigate.
I managed to fix the issue by:
* re-enabling background updates on the iPhone Preferences (I don't remembering having disabled that in the past)
* removing manually entered email addresses for LiveTrack and adding back as Contacts from the Connect preferences. For each contact I had to select which email address to use
I tried a test run and immediately the LiveTrack feature started as in the good old days.
So yes, something broke it but definitely it works.