The ConnectCare app needs to have permission to access your camera, which it asks for when you use the app for the first time on any system. If you denied this permission for any reason, you need to make sure to enable this permission before starting a video consultation. Here are some help articles showing you how to enable video permission on different browsers, iOS and Android.
For Android or iOS app: How to Check App Permissions on iOS, Android, Windows, and macOS | WIRED
For Chrome on Mac or Windows: Use your camera & microphone - Android - Google Chrome Help
For Safari on Mac: Change Websites preferences in Safari on Mac - Apple Support