Widgets Page Change/Blank

Hello, we are trying to edit our widgets as we normally would but I guess there was an update to this page. I have deactivated all plugins and even tried a different twenties theme to no avail. The page just comes up blank no matter what. How we we get this back to normal so we can make edits? This seems to be on nearly all of my websites with GP. Thanks!

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