Plugin not working

Hi,

I have the Weight Loss Tracker plug in on my wordpress but for some reason this plugin has stopped producing the graph on the URL stated above. (it just shows spinning loading sign) I have used the correct shortcode but it seems that something in the back end has disabled it. I have checked it against my current plugins for clashes and I can not seem to find anything.

Version of the weight loss tracker is: 5.0.4

Please can you help?

Thanks,

The page I need help with: [log in to see the link]