Adobe announced back in 2017 that Flash Player was going away on Dec 31 2020. In coordination, all of the major browser developers announced that they would be dropping support for browser plug-ins across the board.
You can check out that background and the corresponding browser roadmaps in our original announcement from 2017:
https://theblog.adobe.com/adobe-flash-update/
The moral of the story here is that SmileBox has had three years to update their application. You'll need to ask them for a solution or find an alternative product to use.