Out of the blue earlier today, when a phone call came in, I answered on my watch but when the connection went through and I started talking I could not hear anything on my SG Sport Watch . I could faintly hear the voice through my iPhone6 in my pant pocket. It happened two more times. I called Apple Care and had a great experience with their help. We tried powering off then on the watch-no luck. Then unpairing and re-pairing the watch and phone-no luck. Finally rebooting the watch-BINGO...PAY DIRT. Everything was good with the world. So I think the last step should be the first if this should happen to anyone. Cheers. And I hope no one ever has to actually use this tip! 
