The error occurs if the microphone, camera, or access to them is disabled on your computer or browser.
First of all, check if the microphone and camera work with other online services.
Also, try these:
- Ensure that the camera and microphone are connected to the computer (use external or built-in devices);
- Temporarily disable antivirus and firewall (instructions for Windows, macOs) as they may interfere with the browser in providing access to the camera and microphone;
- Close third-party apps that are using your microphone and camera
- Check if the browser has an access to your microphone and camera (see: Providing access to the webcam and microphone)
Scanning for new devices can also be helpful:
- Press Win + R;
- Enter devmgmt.msc;
- Choose Action > Scan for hardware changes.
- Try to pass the System check again