Your browser must support webRTC. Please see the list of supported browsers and more information here.
If a “Failed to allocate resource: permission denied” alert is displayed, (camera or audio) configure your browser’s alerts to allow permissions on the site for webcam and audio.
You will usually find the Settings menu at the end or beginning of the browser’s URL box. If not, the browser you are using does not have permission to use the camera/audio and you will need to change the permissions in the OS settings. Open your OS settings, and allow Chrome camera privileges in the system. This is a common issue for iOS users after upgrading to Mojave.