U2718Q, no audio?

I bought this U2718Q yesterday. The display looks good for me. However, there is no audio from it:
1. I checked the previous posts, and followed the steps to unplug/plug; unpower/power again.
2. I connected from the Surface Pro mDP out port to the U2718Q DP in port (no audio)
I connected from a desktop HDMI out port to the U2718Q HDMI in port (no audio)
I checked the cable, replaced the cable.
3. From right click the sound button, when I configure the U2718Q audio, there is no audio coming out.