Mac – Skype for Business has no sound and I am not able to make calls

So first of all I have checked sounds settings, tested normal Skype client, updated Skype for Business, uninstalled and re-installed it, etc. and my microphone and speaker are working as expected in regular Skype client and in general.

But when I join a meeting with Skype for Business, I can't hear anyone speak and they don't seem to see me as a participant in the conversation. My mic is muted right away and the button is disabled. I have tested meetings created by my self, and ones created by others. I also seem to being having troubles calling others (one to one). It gives me the classic sound from Skype when calling but the others are not receiving the call. My college then tried to call me and that worked fine, calls and sound was fine.

I just experienced that when joining the meeting my colleague says I have a status as "Not in the call" when he howers over my icon and after waiting a bit I actually got a message from Skype saying that the call could not be made. So maybe when I am joining the meeting I am actually not with the voice call – and I cant make calls directly to others.

Making calls/joining meetings from my windows laptop works.. but not from my macbook.

Any ideas how to resolve this?

I am running Skype for Business version 16.26.19 on a 15" 2018 MacBook Pro running macOS Mojave.