I had this issue too none of the suggestions worked. What I had to do was select pair manually and enter the code from the watch into my phone instead of scanning the watch. Now updating
Elphaba91
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Scotland