Hi, I currently have a Marantz SR4200 AV receiver and a Hisense 55K3110PW TV. I have purchased an optical cable to connect the two units. This doesn’t appear to be working as there is no sound coming from the speakers. I have very limited knowledge on this and I’m not sure if the two appliances are compatible or there is something in the set up that I have missed. Any information would be fantastic. Thanks