Loud buzzing on web calls VideoBridge

Hi - I’ve installed Jitsi videobridge on an AWS EC2 instance. The video seems fine but as soon as a second call / connection comes in there’s a very loud buzzing on one of the devices. I’ve tried this with the Android app and 2 laptops.

Anyone know why this could be happening?

We had seen this and normally is a problem with a device … Or you say that all participants audio is like that?