I had my TV & soundbar working perfectly using HDMI ARC. However as I had a problem with Amazon Prime a technician at LG suggested a factory reset which solved my Amazon problem, but resulted in the HDMI ARC connection to the sound bar not working. Settings are all set up correctly on both TV & soundbar. This seems to make no sense at all. I have had to use an optical lead, not my ideal a son I have to use blu taco to stop it falling out of the TV.