If you're using MacOS and your browser has not previously been used for video calling, you will need to allow access in System Preferences.
Open System Settings (or System Preferences on older versions of MacOS) and click "Privacy & Security".
To enable media device access, select "Microphone" or "Camera". For screensharing, select "Screen & System Audio Recording"
Navigate to the browser that you wish to use Pencil Spaces with.
If your browser doesn't have a checkmark next to it, select the checkmark and save your changes.
You will be asked to "Quit & Reopen" your browser to apply these changes.
Once your browser restarts, you should be able to join calls or share your screen as normal