Only the video, not the audio, worked when I streamed a program or movie. I thought I had a bad HDMI outpu port. I spent 2-1/2 hours on the phone last week with HP techs in search of a solution and did not find one. Yesterday,
I found my computer has two options for sound. One runs the sound to the HDMI port, the other runs the sound to the computer's speakers. I changed the default to the HDMI output port and, viola! Sound!
Why the technicians did not know this is beyond me. I'm posting this for others who may be experiencing the same issue.