If you are playing from the web browser, on your mobile device, the geolocation will try to run.
If you are using an IOS device, you will be instantly directed to the app store to download GeoGuard Location Validator and if you're using Android, you will see a popup notification explaining that you must download GeoGuard.
Follow the steps below and accept/allow the app to locate you.
Once you have completed this step, return back to the web browser and Geolocation will automatically run for you.