@Judoal,

Do you know if the feature has ever worked on your app? It could be that the permission was never given allowing your phone mic to be used. I would recommend uninstalling and reinstalling the Tapo app, along with any related data - this should force the app to request the permissions and will also help remove anything that may have been getting in the way when the app is reinstalled.

What Type of Phone Do You Have? What OS are you running?