Peculiar problem with MacBook Air bluetooth connection to receiver

I had my MacBook Air paired and working with my receiver (Harman Kardon 3770) for a year or more. Recently I get no sound when the two are paired, even though both the MBA and the HK show as paired. My iPad works fine with a bluetooth connection to the same receiver. And my MBA works fine with a bluetooth connection to my headphones. I've deleted the HK 3770 device from the MBA bluetooth devices and adding it back. Still doesn't work. Any ideas???

THANKS SO MUCH!