1. You may have to turn the TV optical audio output on and the TV internal speakers off in the TV audio menu.
2. You may have to change the TV audio output type to get surround sound. Same menu as above.
3. You may have to assign the optical connection you used on the receiver to an input. Here is a link to the page of receiver owners manual that is relevant. https/www.manualslib.com/manual/278956/Harman-Kardon-Avr-340.html?page=22#manual