Acer KA241Y audio problem

I have bought a new Acer KA241Y display monitor and I can’t get the sound coming from the monitor’s integrated 2 x 4 W speakers. I have tried both volume sliders on the monitor itself and on the Windows 10 settings, nothing happens.

I did the troubleshooting thing and it didn’t find anything. It says the device KA241Y is working properly and I also updated the driver. I can see the green bars “jumping” up and down on the sound settings when playing music but I can’t hear anything.

Also when I connect my headphones to the monitors’ headphone plug, the sound works fine. Before I contact the seller, do you have any ideas what am I doing wrong here or is it broken?