As of December 17th, 2019, we became aware of a number of users on the Windows 7 OS facing issues attempting to use Screenshare and GoLive. This issue manifests as a blank black screen when attempting to use the feature.
To make sure that your settings are optimal, you can check to see if the following is enabled:
User Settings > Voice & Video > 'Use our latest technology to capture your screen' Turn On
If this does not correct the issue, our sincerest apologies. The team is aware of a broader issue and investigating. We do not yet have an ETA on when this will be corrected.