Click on the padlock icon in the browser address bar (in the top left corner next to URL)
Click on Allow for Camera, Microphone, and Sound
If it doesn't appear here, then you can check in your Chrome settings if permissions are given.
Click the three dots in the upper right corner and click Settings
Click Privacy & Security
Click Site settings
Click Filter website by site
Enter name demodesk in the search bar
Make sure that it says Allow next to each permission.
If this does not solve it, then probably your system is blocking permissions. Go here to solve it.