As a participant in a conference, first check that your webcam is correctly connected to your device. Then check that you have given your browser access to your webcam. If you are already in a conference, disconnect your video conference by clicking the webcam icon and then clicking the webcam icon again to share your webcam again. Make sure the browser can access your webcam. If you are using multiple webcams (for example, a built-in webcam and an external webcam), make sure you select the correct device. If you have blocked access to your webcam in the browser, you will need to reactivate your webcam in the browser settings. With a diagnostic tool at test.webrtc.org you can rule out possible problems with the WebRTC standard. The tool is provided by Google LLC. If you see "Another application is using your webcam" or "NotReadableError: video source could not be started", check to see if another application is not using your webcam. Close the applications and share your webcam again.