Hello Christina,
You can try to remove the charts widget from your widgets folder, if you're not using it anywhere else. That should solve your problem. If you still need it on another page, you could attempt to update the widget, or simply remove it and add it again.
Dragos is correct, remove the widget from the widget folder. If there is still an error, please clear your browser cache, remove the deployment folder and redeploy. This issue sounds like a caching problem