If you're using a mobile device you'll need to use the app instead of browser, as mobile devices don't have the operating power required for the browser version of games
You will need minimum iOS 11.0 or later.
Android Devices and Chromebooks
You will need a minimum Android v5.0 or later.
The latest version of the Sumdog app is version 79.0.0.
The minimum version of the Sumdog app that will run is 57.0.0. If you are using an older version of the Sumdog app, it will not run until you update to the newest version.