Question Asus VC279H, no sound over 3.5mm audio port

[Matt3520]

I have Asus monitor with bulit in speakers that is connected to Intel NUC7i7BNH over HDMI. I have sound over HDMI. When I connect monitor and NUC via 3.5mm audio cabel I have no sound. If I plug headphones in NUCs audio jack, headphones work.

 

[Matt3520]

Apparently, when monitor is connected over HDMI, it excepts audio input over HDMI. Audio jack is only if I connect monitor over VGA.