You will get this error when Zaurus cannot access the camera or microphone. Always check your browser settings before opening Zaurus via the web-browser.

If the settings are correct, and it is still not working, it may be your OS is blocking the browser from accessing the microphone and/or camera. 

In both Windows 10 and MacOS, the settings to allow or block access to the devices can be managed from the privacy settings from the operation system.