Local audio not heard by remote

Yesterday for the first time I used the audio communications function in TV (v13) between my PC (I'm the local, Desktop Win10 x64, LogiTech G930) to my friend's new laptop. Everything work and we were pleased. Tonight we tried again, I can hear him (he is the remote) but he cannot hear me (I'm the local). His speakers are unmuted and the volume is all the way up. If I look at the TV audio settings on my PC and tap the mic I can see that the mic is working on my PC.