Get into your Denon menu settings and make sure set to ARC and that everything else is where it should be. You haven't said that you were using external speakers but if you are your tv speakers should be off.
Sound output from TV to Denon AVR-X2400H
Just got a new Sony X85J TV. Using the HDMI ARC connections. Volume works but I have to turn the TV volume up as high as it will go then turn the volume up on Denon to what I would consider abnormally high level (~80%) to get the sound to be what I would consider normal listening levels. Am I mis-configured?
I also have decent external DAC hooked up to the Denon I use for streaming music. I suppose I could go optical out of TV to DAC?