talkback doesn't work on cubase 10.5

ok… i just updates to 10.5.20
but still the problem persists
the performer is not able to hear me on Cubase 10.5 but he can hear me on Cubase 10…
its the same project… so i don’t think there could be any errors in routing…
have checked thoroughly…
all talkback buttons are on… in vst connections talkback routing is done… checked the volume level of talkback… nothing seems wrong but still the performer can’t hear me on cubase 10.5

regarding the webcam… what i meant… is there a way to switch off permanently till the time i switch it on…
what i mean even if i switch it off and close the project… the moment i open the project the next time…i find the webcam on…