Cisco Engineering has deployed a software fix to address this issue.
Posted 20 days ago. Sep 28, 2017 - 16:00 UTC
Cisco Engineering is investigating an issue where calling and white board functionality is unavailable for some Spark Board devices.
To work around the issue, users may restart the Spark Board manually by tapping the Spark Board name on the top of the screen, select settings and then select restart. Upon reboot, services will be restored.
Engineering is working on a software update for the Spark Boards to restore service.