ZOOM and HDMI from laptop to big screen AUDIO question

I bought a zoom concert recently. Wanting to watch it on my big screen I thought I would hook up HDMI cable from the laptop where i WAS streaming it to an HDMI input on the big screen. Before the zoom concert became available, I watched music videos on you tube and picture and audio traveled across the HDMI cable just fine. When it was time to zoom and the person signing us in was talking to others and eventually us to get us signed in I realized I only had sound on the laptop, not on my bigscreen and not on my amp and speakers that run off the big screen audio outputs! (This had all been ok with youtube). I never had a chance to ask the sign in person why I was not getting audio, but was able to hurriedly hook up some 2.1 laptop speakers to the laptop that gave me enough sound from the concert to make it worthwhile.

Can a zoom promoter/provider cut off sound to the HDMI port out from the device you are streaming on? The picture ran out fine, but not the sound.