If you or your client can’t see the other person, the person whose camera appears not to be working should try the following steps to fix things.
When you first started an online session, you will have been asked to give permission for your web browser to access your camera. If you didn’t allow this, you will need to go into the browser settings to allow this. Go to https://app.bilateralbase.com/pre-call-test when you reach the camera test, you will see instructions suitable for your browser on how to allow the web browser to access your camera
Your operating system may have privacy features that are preventing access to your camera.