If your Presentation screen stops working, please try refreshing the screen by clicking the refresh button on the top right of the screen.
Another step to try if you are still having issues is to restart the Virbela Application. If it continues then restart your computer altogether.
Note: We at Virbela would greatly appreciate it if you could take the time to submit a bug report if this should happen to you. You can find the process to do so by following our Knowledgebase Article How to Report a Bug.
Note: If you still have issues after trying the above, please open a ticket with us by emailing help@virbela.com.