Had the same problem with my Airpods. It is due to too many bluetooth connections to your iphone. Music still works but not the phone functions. In my case, it was my Tile trackers causing the problem.Iphone 8 with new IOS12 updates
my bluetooth ear bud works with all APs except the phone! icon disappears and no bluetooth function for any incoming calls or outgoing calls. who else has this problem?
thats ridiculous - i have several bluetooth options (wireless radio in home etc) all of which are turned off. I only use the ear bud and it worked until I updated - my mistake (again) for trusting Apple to preform due diligence.
still looking for an answer