Hi there:
In some rare cases, it is necessary to edit config.txt to force HDMI mode (as opposed to DVI mode, which does not send sound). You can do this by editing /boot/config.txt and setting hdmi_drive=2, then rebooting for the change to take effect.
<LINK_TEXT text=“https://www.raspberrypi.org/documentati … -config.md”>https://www.raspberrypi.org/documentation/configuration/audio-config.md</LINK_TEXT>