You can try following solutions for general mic and or webcam issues irrespective of the Operating System you are using:
a) General issues with audio/video/desktop feeds can be encountered during all steps of the setup wizard as the inputs start receiving data. If all of a sudden, you see the error screen, it might again be due to the mic/cam permissions. If it’s not that, then another thing to check is that you can use your mic/cam in a 3rd party Chrome webpage. This is a good tool to use: https://webcammictest.com/.
b) If still having issues with the cam/mic, check if your camera and mic works using a 3rd party program such as Skype, this is a good way to rule out cam/mic issues. Around 95% of the mic/cam issues are due to the users’ mic/cam permissions either in browser or set by OS for MAC users.
c) Sometimes, 3rd party programs lock access to the cam and mic. You can try restart the machine/computer. When you log back in, only open the necessary programs they need to run the plugin (ideally just Chrome/Edge). This might free up access to use the cam/mic.