In case you reconfigured the access settings for the Microphone, you can check and change the settings if needed.
Similarly, once you encounter the headset not responding in Fortnite on Xbox One, Switch, or PS 4, it is also necessary to reconnect the microphone in case of any wrongdoings in the connection.
The tool will then scan your computer for any missing or outdated drivers.
If you haven't provided the information already, please share the following to help Epic Games: How can this bug be reproduced? Only the character voices are missing.