Question Screen mirroring without sound on cisco webex


I did a screen mirroring via wifi from a huawei p30 lite and from a 10 lite on an LG TV. The sound only worked on the phone when I was on the Cisco Webex application. On youtube, the sound is heard on the TV, as it should be, and on fb, only on cisco it doesn't work, I don't understand why. I have nothing to choose in the application settings.