Latitude E5440 - No sound over HDMI

Greetings!

My Latitude E5440 - Windows 10 Pro (64bit) does not allow for sound over HDMI.

If I go to Playback Devices, the Audio Receiver (Onkyo TX-NR525) is available. If I set it as default device for playback, I get no sound. If I test the speakers, I get no sound.

I have updated to the latest driver from Dell for the Display Driver using Dell Command Update (Intel HD 10.18.15.4281). I have also ensured all other drivers are installed from Command Update.

I have updated to the latest driver for the sound card (RealTEK 6.0.1.7541)

Any ideas? I have Chromebook that works just fine using the same HDMI cable and receiver, so those devices should be fine.