I see the tracking script executing in the browser console.
Maybe something is blocking your WP-Cron queue preventing the statistics from being collected.
Can you install the Advanced Cron Manager plugin and see if there is something stuck on top of the cron tasks list, and also if the Koko cron task is there?
Saving the Koko settings should re-create the cron task if needed.
Hope that helps. If you have any questions, please let me know!