When you see a red bar with an error code that ends at -2006, it is most likely your web-app cannot access the camera or the microphone.
You can view and change this by following the steps below.
Firefox:
In Firefox these settings are under Options -> Privacy en security -> Permissions -> Camera (or microfoon)
Chrome:
In Chrome you can simply go to chrome://settings/content en change the settings for the camera and microphone there.
Edge:
Go to Settings and then press Advanced. Here you will find a button 'manage permissions'. Click it and in the next screen you can see which apps have which permissions.
Click on op Alterdesk and change the permissions accordingly.
MacOS
Open Safari and go to the web-app. When you go there, go to Safari's prefferences and open the Webistes tab in the next screen. Here you can choose either camera or micropphone. Select the relevant device and make your changes.
Windows:
Windows may prevent access to the camera. Since update 1903, Windows has settings to restrict camera functionality to specific app groups.
To find these settings, perform the following:
Open the start menu and type Camera Privacy Settings.
This opens a menu where you can allow or deny certain Microsoft applications access to the camera, deny the camera to be used by the system at all, or to allow or deny non-microsoft apps access to the camera.