Before you start a test for the first time, you have to allow the Seamless Desktop Recorder to access your microphone and camera.
You may have accidentally blocked this access during setup. Review this article to learn how to reset these permissions so you can continue with your test.
How to reset permissions in Firefox
Click the hamburger icon, and then click Preferences.
Go to the Privacy & Security section, and then select the Settings for the permission you need to reset (Camera or Microphone).
In the window that pops up, open the dropdown menu for the UserTesting recorder and change the selection to Allow. Click Save Changes when you're done.